HttpClient client = new DefaultHttpClient();
HttpPost postRequest = new HttpPost("https://www.google.com/accounts/ClientLogin");
List nameValuePairs = new ArrayList(2);
nameValuePairs.add(new BasicNameValuePair("accountType","GOOGLE"));
nameValuePairs.add(new BasicNameValuePair("Email",senderEmail));
nameValuePairs.add(new BasicNameValuePair("Passwd","xxxxx"));
nameValuePairs.add(new BasicNameValuePair("service","ac2dm"));
nameValuePairs.add(new BasicNameValuePair("source","Uygulama"));
try {
   postRequest.setEntity(new UrlEncodedFormEntity(nameValuePairs));
   postRequest.setHeader("Content-Type", "application/x-www-form-urlencoded");
   HttpResponse response = client.execute(postRequest);
 
   InputStream inputStream  = response.getEntity().getContent();
   BufferedReader rd = new BufferedReader(new InputStreamReader(inputStream));
   String line;
   while ((line = rd.readLine()) != null) {
      Log.d(TAG,":"+line);
   }
   client.getConnectionManager().closeExpiredConnections();
} catch (IOException e) {
   client.getConnectionManager().closeExpiredConnections();
   e.printStackTrace();
}

private void register() {
   Intent registrationIntent = new Intent("com.google.android.c2dm.intent.REGISTER");
   registrationIntent.putExtra("app", PendingIntent.getBroadcast(this, 0, new Intent(), 0));
   registrationIntent.putExtra("sender", emailOfSender);
   startService(registrationIntent);
}

private void unregister() {
   Intent unregIntent = new Intent("com.google.android.c2dm.intent.UNREGISTER");
   unregIntent.putExtra("app", PendingIntent.getBroadcast(this, 0, new Intent(), 0));
   startService(unregIntent);
}

public class C2DMReceiver extends BroadcastReceiver {
   private static String TAG = "C2DMReceiver";
 
   public void onReceive(Context context, Intent intent) {
      if (intent.getAction().equals("com.google.android.c2dm.intent.REGISTRATION")) {
         handleRegistration(context, intent);
      }
   }
 
   private void handleRegistration(Context context, Intent intent) {
      String registration = intent.getStringExtra("registration_id");
      if (intent.getStringExtra("error") != null) {
         Log.d(TAG, "error: " + intent.getStringExtra("error"));
      } else if (intent.getStringExtra("unregistered") != null) {
         // kendi sunucumuza registration_id'yi sileceğiz...
      } else if (registration != null) {
         // kendi sunucumuza registration_id'yi gonderecegiz...
      }
   }
}

public static String sendMessage(registrationId,authorizationId,data){
   String retStr ="";
   try {
 
      String registrationId = registrationId;
      String collapseKey = URLEncoder.encode(data, "UTF-8");
 
      URL url = new URL("https://android.apis.google.com/c2dm/send");
      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      connection.setDoOutput(true);
      connection.setRequestMethod("POST");
      connection.setRequestProperty("Authorization", "GoogleLogin auth="+authorizationId);
      OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
      writer.write("registration_id=" + registrationId);
      writer.write("&collapse_key=" + collapseKey);
      writer.write("&data.SERVER_MESSAGE=" + data);
      writer.close();
 
      if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
         InputStream is = connection.getInputStream();
         byte[] buffer = new byte[1024];
         int bytesRead = 0;
 
         while ((bytesRead = is.read(buffer)) != -1)
            retStr = retStr + new String(buffer, 0, bytesRead);
      } else {
         retStr = "error";
      }
   } catch (MalformedURLException e) {
      e.printStackTrace();
   } catch (IOException e) {
   e.printStackTrace();
}
return retStr;
 
}

public class C2DMReceiver extends BroadcastReceiver {
   private static String TAG = "C2DMReceiver";
 
   public void onReceive(Context context, Intent intent) {
      if (intent.getAction().equals("com.google.android.c2dm.intent.REGISTRATION")) {
         handleRegistration(context, intent);
      } else if (intent.getAction().equals("com.google.android.c2dm.intent.RECEIVE")) {
         handleMessage(context, intent);
      }
   }
 
   private void handleRegistration(Context context, Intent intent) {
      String registration = intent.getStringExtra("registration_id");
      if (intent.getStringExtra("error") != null) {
         Log.d(TAG, "error: " + intent.getStringExtra("error"));
      } else if (intent.getStringExtra("unregistered") != null) {
         // kendi sunucumuzdan registration_id'yi sileceğiz...
      } else if (registration != null) {
         // kendi sunucumuza registration_id'yi gonderecegiz...
      }
   }
}
 
   private void handleMessage(Context context, Intent intent) {
      String message = intent.getExtras().getString("SERVER_MESSAGE");
      Log.d(TAG, "message: " + message);
   }
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.android.c2dm"  android:versionCode="1" android:versionName="1.0">
   <permission android:name="com.example.android.c2dm.permission.C2D_MESSAGE" android:protectionLevel="signature" />
   <uses-permission android:name="com.example.android.c2dme.permission.C2D_MESSAGE" />
   <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
   <application android:icon="@drawable/icon" android:label="@string/app_name">
 
      <receiver android:name=".C2DMReceiver" android:permission="com.google.android.c2dm.permission.SEND">
          <!-- Receive the actual message -->
          <intent-filter>
              <action android:name="com.google.android.c2dm.intent.RECEIVE" />
              <category android:name=" com.example.android.c2dm" /> 
          </intent-filter>
          <!-- Receive the registration id -->
          <intent-filter>
              <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
              <category android:name="com.example.android.c2dm" />
          </intent-filter>
      </receiver>
.
.
.
    </application>
</manifest>