diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index d80ff689..d52a6a15 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -7,6 +7,9 @@
 		  a:versionName="1.2.23">
 
 	<uses-permission a:name="android.permission.VIBRATE"/>
+	<uses-permission a:name="android.permission.INTERNET"/>
+	<uses-permission a:name="android.permission.ACCESS_NETWORK_STATE"/>
+	<uses-permission a:name="com.android.vending.BILLING" />
 
 	<uses-sdk a:minSdkVersion="4"
 			  a:targetSdkVersion="8"/>
@@ -16,6 +19,7 @@
 				 a:name=".ApplicationContext">
 
 		<activity a:name=".CalculatorActivity"
+				  a:windowSoftInputMode="adjustPan"
 				  a:label="@string/c_app_name">
 
 			<intent-filter>
@@ -92,5 +96,17 @@
 		<activity a:name=".CalculatorPlotActivity"
 				  a:label="@string/c_plot_graph"/>
 
+		<activity a:name="com.google.ads.AdActivity"
+				  a:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"/>
+
+		<service a:name="net.robotmedia.billing.BillingService"/>
+		<receiver a:name="net.robotmedia.billing.BillingReceiver">
+			<intent-filter>
+				<action a:name="com.android.vending.billing.IN_APP_NOTIFY"/>
+				<action a:name="com.android.vending.billing.RESPONSE_CODE"/>
+				<action a:name="com.android.vending.billing.PURCHASE_STATE_CHANGED"/>
+			</intent-filter>
+		</receiver>
+
 	</application>
 </manifest>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 8f971170..603af87e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -88,6 +88,14 @@
 			<systemPath>${additionalLibs}/GoogleAdMobAdsSdk-4.3.1.jar</systemPath>
 		</dependency>
 
+		<dependency>
+			<groupId>android-billing-library</groupId>
+			<artifactId>android-billing-library</artifactId>
+			<version>0.1</version>
+			<scope>system</scope>
+			<systemPath>${additionalLibs}/AndroidBillingLibrary.jar</systemPath>
+		</dependency>
+
 		<dependency>
 			<groupId>com.intellij</groupId>
 			<artifactId>annotations</artifactId>
diff --git a/res/layout-land/main_calculator.xml b/res/layout-land/main_calculator.xml
index bacab745..9a81dc59 100644
--- a/res/layout-land/main_calculator.xml
+++ b/res/layout-land/main_calculator.xml
@@ -15,6 +15,7 @@
 
 	<LinearLayout
 			a:layout_width="fill_parent"
+			a:id="@+id/ad_parent_view"
 			a:layout_height="fill_parent"
 			a:orientation="vertical"
 			a:layout_gravity="center">
diff --git a/res/layout-land/main_cellphone.xml b/res/layout-land/main_cellphone.xml
index 239fb97b..fd84a51b 100644
--- a/res/layout-land/main_cellphone.xml
+++ b/res/layout-land/main_cellphone.xml
@@ -10,6 +10,7 @@
 	<LinearLayout
 			a:layout_width="fill_parent"
 			a:layout_height="fill_parent"
+			a:id="@+id/ad_parent_view"
 			a:orientation="vertical"
 			a:layout_gravity="center">
 
diff --git a/res/layout-port/main_calculator.xml b/res/layout-port/main_calculator.xml
index aa51b1d6..4776a3bb 100644
--- a/res/layout-port/main_calculator.xml
+++ b/res/layout-port/main_calculator.xml
@@ -15,6 +15,7 @@
 	<LinearLayout
 			a:layout_width="fill_parent"
 			a:layout_height="fill_parent"
+			a:id="@+id/ad_parent_view"
 			a:orientation="vertical"
 			a:layout_gravity="center">
 
diff --git a/res/layout-port/main_cellphone.xml b/res/layout-port/main_cellphone.xml
index 2f2fd2c4..cdea70f1 100644
--- a/res/layout-port/main_cellphone.xml
+++ b/res/layout-port/main_cellphone.xml
@@ -9,6 +9,7 @@
 	<LinearLayout
 			a:layout_width="fill_parent"
 			a:layout_height="fill_parent"
+			a:id="@+id/ad_parent_view"
 			a:orientation="vertical"
 			a:layout_gravity="center">
 
diff --git a/res/values-ru/text_strings.xml b/res/values-ru/text_strings.xml
index d0d9c85a..d425bc56 100644
--- a/res/values-ru/text_strings.xml
+++ b/res/values-ru/text_strings.xml
@@ -164,5 +164,7 @@
 	<string name="c_calc_use_back_button_as_prev_title">Использовать кнопку назад как назад по истории</string>
 
 	<string name="c_warning">Внимание</string>
+	<string name="c_error">Ошибка</string>
+	<string name="c_billing_error">Биллинг не поддерживается!</string>
 
 </resources>
\ No newline at end of file
diff --git a/res/values/default_values.xml b/res/values/default_values.xml
index afb1d38c..1ceed36f 100644
--- a/res/values/default_values.xml
+++ b/res/values/default_values.xml
@@ -58,4 +58,7 @@
 	<string name="p_calc_haptic_feedback_duration_key">org.solovyev.android.calculator.CalculatorActivity_calc_haptic_feedback_duration_key</string>
 	<string name="p_calc_haptic_feedback_duration">" "</string>
 
+	<string name="p_calc_ad_free_key">org.solovyev.android.calculator_ad_free_application</string>
+	<string name="p_calc_ad_free">false</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/values/text_strings.xml b/res/values/text_strings.xml
index 0af0ee85..74b1e29f 100644
--- a/res/values/text_strings.xml
+++ b/res/values/text_strings.xml
@@ -164,5 +164,7 @@
 	<string name="c_calc_use_back_button_as_prev_title">Use Back button as history prev</string>
 
 	<string name="c_warning">Warning</string>
+	<string name="c_error">Error</string>
+	<string name="c_billing_error">Billing is not supported!</string>
 
 </resources>
\ No newline at end of file
diff --git a/res/xml/main_preferences.xml b/res/xml/main_preferences.xml
index c730f26f..c3bd8ca8 100644
--- a/res/xml/main_preferences.xml
+++ b/res/xml/main_preferences.xml
@@ -2,6 +2,14 @@
 
 <PreferenceScreen xmlns:a="http://schemas.android.com/apk/res/android"
 				  xmlns:range="http://schemas.android.com/apk/res/org.solovyev.android.calculator">
+
+<!--	<SwitchPreference
+			a:key="@string/p_calc_round_result_key"
+			a:summary="@string/c_calc_round_result_summary"
+			a:title="@string/c_calc_round_result_title"
+			a:defaultValue="false"
+		/>-->
+
 	<PreferenceCategory a:title="@string/c_prefs_calculations_category">
 
 		<android.preference.CheckBoxPreference
diff --git a/src/main/java/org/solovyev/android/AndroidUtils.java b/src/main/java/org/solovyev/android/AndroidUtils.java
index 7275a27b..432d78da 100644
--- a/src/main/java/org/solovyev/android/AndroidUtils.java
+++ b/src/main/java/org/solovyev/android/AndroidUtils.java
@@ -15,6 +15,9 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TabHost;
 import android.widget.TextView;
+import com.google.ads.AdRequest;
+import com.google.ads.AdSize;
+import com.google.ads.AdView;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -24,38 +27,38 @@ import org.jetbrains.annotations.NotNull;
  */
 public final class AndroidUtils {
 
-    // not intended for instantiation
-    private AndroidUtils() {
-        throw new AssertionError();
-    }
+	// not intended for instantiation
+	private AndroidUtils() {
+		throw new AssertionError();
+	}
 
-    public static void centerAndWrapTabsFor(@NotNull TabHost tabHost) {
-        int tabCount = tabHost.getTabWidget().getTabCount();
-        for (int i = 0; i < tabCount; i++) {
-            final View view = tabHost.getTabWidget().getChildTabViewAt(i);
-            if ( view != null ) {
-                if (view.getLayoutParams().height > 0) {
-                    // reduce height of the tab
-                    view.getLayoutParams().height *= 0.8;
-                }
+	public static void centerAndWrapTabsFor(@NotNull TabHost tabHost) {
+		int tabCount = tabHost.getTabWidget().getTabCount();
+		for (int i = 0; i < tabCount; i++) {
+			final View view = tabHost.getTabWidget().getChildTabViewAt(i);
+			if (view != null) {
+				if (view.getLayoutParams().height > 0) {
+					// reduce height of the tab
+					view.getLayoutParams().height *= 0.8;
+				}
 
-                //  get title text view
-                final View textView = view.findViewById(android.R.id.title);
-                if ( textView instanceof TextView) {
-                    // just in case check the type
+				//  get title text view
+				final View textView = view.findViewById(android.R.id.title);
+				if (textView instanceof TextView) {
+					// just in case check the type
 
-                    // center text
-                    ((TextView) textView).setGravity(Gravity.CENTER);
-                    // wrap text
-                    ((TextView) textView).setSingleLine(false);
+					// center text
+					((TextView) textView).setGravity(Gravity.CENTER);
+					// wrap text
+					((TextView) textView).setSingleLine(false);
 
-                    // explicitly set layout parameters
-                    textView.getLayoutParams().height = ViewGroup.LayoutParams.FILL_PARENT;
-                    textView.getLayoutParams().width = ViewGroup.LayoutParams.WRAP_CONTENT;
-                }
-            }
-        }
-    }
+					// explicitly set layout parameters
+					textView.getLayoutParams().height = ViewGroup.LayoutParams.FILL_PARENT;
+					textView.getLayoutParams().width = ViewGroup.LayoutParams.WRAP_CONTENT;
+				}
+			}
+		}
+	}
 
 	public static void addTab(@NotNull Context context,
 							  @NotNull TabHost tabHost,
@@ -75,7 +78,7 @@ public final class AndroidUtils {
 
 
 	/**
-	 * @param context context
+	 * @param context		context
 	 * @param appPackageName - full name of the package of an app, 'com.example.app' for example.
 	 * @return version number we are currently in
 	 */
@@ -88,5 +91,23 @@ public final class AndroidUtils {
 		return -1;
 	}
 
+	@NotNull
+	public static AdView createAndInflateAdView(@NotNull Activity activity, int layoutId, String admobAccountId) {
+		// Create the adView
+		final AdView adView = new AdView(activity, AdSize.BANNER, admobAccountId);
+
+		// Lookup your LinearLayout assuming it’s been given
+		// the attribute android:id="@+id/mainLayout"
+		final ViewGroup layout = (ViewGroup) activity.findViewById(layoutId);
+
+		// Add the adView to it
+		layout.addView(adView);
+
+		// Initiate a generic request to load it with an ad
+		adView.loadAd(new AdRequest());
+
+		return adView;
+	}
+
 }
 
diff --git a/src/main/java/org/solovyev/android/calculator/ApplicationContext.java b/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
index 2d440493..24dc38c3 100644
--- a/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
+++ b/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
@@ -1,5 +1,6 @@
 package org.solovyev.android.calculator;
 
+import net.robotmedia.billing.BillingController;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -9,15 +10,36 @@ import org.jetbrains.annotations.NotNull;
  */
 public class ApplicationContext extends android.app.Application {
 
-	@NotNull
-    private static ApplicationContext instance;
+	public static final String AD_FREE_APPLICATION = "ad_free_application";
+	public static final String AD_FREE_APPLICATION_P_KEY = "org.solovyev.android.calculator_ad_free_application";
 
-    public ApplicationContext() {
+	@NotNull
+	private static ApplicationContext instance;
+
+	public ApplicationContext() {
 		instance = this;
-    }
+	}
 
 	@NotNull
 	public static ApplicationContext getInstance() {
 		return instance;
 	}
+
+	@Override
+	public void onCreate() {
+		super.onCreate();
+		/*BillingController.setDebug(true);
+		BillingController.setConfiguration(new BillingController.IConfiguration() {
+
+			@Override
+			public byte[] getObfuscationSalt() {
+				return new byte[]{81, -114, 32, -127, -32, -104, -40, -15, -47, 57, -13, -41, -33, 67, -114, 7, -11, 53, 126, 82};
+			}
+
+			@Override
+			public String getPublicKey() {
+				return "org.solovyev.android.calculator";
+			}
+		});*/
+	}
 }
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
index c3ce2267..bb373b44 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
@@ -23,6 +23,7 @@ import android.view.*;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
+import com.google.ads.AdView;
 import jscl.AngleUnit;
 import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
@@ -38,6 +39,7 @@ import org.solovyev.android.view.FontSizeAdjuster;
 import org.solovyev.android.view.prefs.IntegerPreference;
 import org.solovyev.android.view.prefs.Preference;
 import org.solovyev.android.view.widgets.*;
+import org.solovyev.android.view.widgets.DragEvent;
 import org.solovyev.common.utils.Announcer;
 import org.solovyev.common.utils.Point2d;
 import org.solovyev.common.utils.StringUtils;
@@ -50,6 +52,7 @@ import java.util.Map;
 public class CalculatorActivity extends Activity implements FontSizeAdjuster, SharedPreferences.OnSharedPreferenceChangeListener {
 
 	private static final int HVGA_WIDTH_PIXELS = 320;
+	public static final String ADMOB_USER_ID = "a14f02cf9c80cbc";
 
 	public static class Preferences {
 		@NotNull
@@ -85,6 +88,9 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 
 	private boolean useBackAsPrev = USE_BACK_AS_PREV_DEFAULT;
 
+	@Nullable
+	private AdView adView;
+
 	/**
 	 * Called when the activity is first created.
 	 */
@@ -101,6 +107,8 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 		super.onCreate(savedInstanceState);
 		setLayout(preferences);
 
+		//adView = AndroidUtils.createAndInflateAdView(this, R.id.ad_parent_view, ADMOB_USER_ID);
+
 		if (customTitleSupported) {
 			try {
 				getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.calc_title);
@@ -617,6 +625,9 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 
 	@Override
 	protected void onDestroy() {
+		if ( adView != null ) {
+			adView.destroy();
+		}
 		super.onDestroy();
 	}
 
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorPreferencesActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorPreferencesActivity.java
index 41a022c2..210d5a0a 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorPreferencesActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorPreferencesActivity.java
@@ -5,9 +5,12 @@
 
 package org.solovyev.android.calculator;
 
+import android.app.AlertDialog;
 import android.content.SharedPreferences;
 import android.os.Bundle;
+import android.preference.Preference;
 import android.preference.PreferenceActivity;
+import net.robotmedia.billing.BillingController;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.view.widgets.VibratorContainer;
 
@@ -24,13 +27,42 @@ public class CalculatorPreferencesActivity extends PreferenceActivity implements
 
 		addPreferencesFromResource(R.xml.main_preferences);
 
+		/*final Preference buyPref = findPreference(ApplicationContext.AD_FREE_APPLICATION_P_KEY);
+		buyPref.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+			// при нажатии на кнопку Убрать рекламу в настройках
+			public boolean onPreferenceClick(Preference preference) {
+				// проверяем поддерживается ли покупка в приложениях
+				if (BillingController.checkBillingSupported(CalculatorPreferencesActivity.this) != BillingController.BillingStatus.SUPPORTED) {
+					// показываем сообщение, что покупка не поддерживается
+					new AlertDialog.Builder(CalculatorPreferencesActivity.this).setTitle(R.string.c_error).setMessage(R.string.c_billing_error).create().show();
+				} else {
+					// проверяем не купил ли пользователь уже нашу опцию
+					boolean purchased = BillingController.isPurchased(getApplicationContext(), ApplicationContext.AD_FREE_APPLICATION);
+					if (!purchased) {
+						// если не купил (или мы просто об этом пока не знаем? пользователь удалял
+						// приложение со всем данными?), то пытаемся восстановить транзакции
+						BillingController.restoreTransactions(CalculatorPreferencesActivity.this);
+						// следующая строка (проверка еще раз не купил ли пользователь приложение) -
+						// не очень правильный подход - вызвав restoreTransactions,
+						// ответ мы получим не сразу
+						purchased = BillingController.isPurchased(getApplicationContext(), ApplicationContext.AD_FREE_APPLICATION);
+						if (!purchased) {
+							// наконец, показываем пользователю стандартное окно для покупки опции
+							BillingController.requestPurchase(CalculatorPreferencesActivity.this, ApplicationContext.AD_FREE_APPLICATION);
+						}
+					}
+				}
+				return true;
+			}
+		});*/
+
 		final SharedPreferences preferences = getPreferenceManager().getSharedPreferences();
 		preferences.registerOnSharedPreferenceChangeListener(this);
 		onSharedPreferenceChanged(preferences, CalculatorEngine.Preferences.roundResult.getKey());
 		onSharedPreferenceChanged(preferences, VibratorContainer.HAPTIC_FEEDBACK_P_KEY);
 	}
 
-	@Override
+		@Override
 	public void onSharedPreferenceChanged(SharedPreferences preferences, String key) {
 		if (CalculatorEngine.Preferences.roundResult.getKey().equals(key)) {
 			findPreference(CalculatorEngine.Preferences.roundResult.getKey()).setEnabled(preferences.getBoolean(key, CalculatorEngine.Preferences.roundResult.getDefaultValue()));
diff --git a/src/misc/doc/GoogleAdMobAdsSdk-4.3.1.jar b/src/misc/doc/GoogleAdMobAdsSdk-4.3.1-javadocs.zip
similarity index 100%
rename from src/misc/doc/GoogleAdMobAdsSdk-4.3.1.jar
rename to src/misc/doc/GoogleAdMobAdsSdk-4.3.1-javadocs.zip
diff --git a/src/misc/src/achartengine-0.7.0-javadocs.zip b/src/misc/doc/achartengine-0.7.0-javadocs.zip
similarity index 100%
rename from src/misc/src/achartengine-0.7.0-javadocs.zip
rename to src/misc/doc/achartengine-0.7.0-javadocs.zip