registerReceiver(new BroadcastReceiver() {
	        @Override
	        public void onReceive(Context context, Intent intent) {
	           Log.d("MyTag", "You have received a message");
	        }
	    }, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));

<uses-permission android:name="android.permission.RECEIVE_SMS" >

Intent intent = new Intent( Intent.ACTION_VIEW, Uri.parse( "sms:" + phoneNumber ) );
intent.putExtra( "sms_body", message ); 
startActivity( intent );

class MySMSApplication extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState) {
  editTextPhone = (EditText) findViewById(R.id.phoneNumber);
  editTextMessage = (EditText) findViewById(R.id.message);
  sendBtn  = (Button)findViewById(R.id.send);
 
sendBtn.setonclickListener(new OnClickListener(){
public void Onclick(){
 sendSMS(editTextPhone.getText().toString(), editTextPhone.getText().toString());
}
});
 
}
 
    private void sendSMS(String phoneNumber, String message)
    {        
        PendingIntent pi = PendingIntent.getActivity(this, 0,
            new Intent(this, Object.class), 0);                
        SmsManager sms = SmsManager.getDefault();
        sms.sendTextMessage(phoneNumber, null, message, pi, null);        
    }    
 
}

 <uses-permission android:name="android.permission.SEND_SMS">

AudioManager am;
am= (AudioManager) getBaseContext().getSystemService(Context.AUDIO_SERVICE);
 
//For Normal mode
am.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
 
//For Silent mode
am.setRingerMode(AudioManager.RINGER_MODE_SILENT);
 
//For Vibrate mode
am.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);

package org.anddev.android.reactonincomingcall;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.telephony.Phone;
import android.telephony.PhoneStateIntentReceiver;
import android.util.Log;
public class ReactOnIncomingCall extends Activity {
   /** Used to recognize Messages from the
  * myPhoneStateChangedHandler. */
   final int PHONECALLSTATE_RECONGNIZE_ID = 0x539;
   /** Will notify us on changes to the PhoneState*/
   PhoneStateIntentReceiver myPsir = null;
  /** This Handler will react on the messages the
   * we made our PhoneStateIntentReceiver myPsir
   * notify us on. */
  Handler myPhoneStateChangedHandler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
     // Recognize the Message by its what-ID
     if(msg.what == PHONECALLSTATE_RECONGNIZE_ID){
        /* Our PhoneStateIntentReceiver myPsir
       * now contains some recent data, we can grab. */
        Phone.State myState = myPsir.getPhoneState();
        // Put the Info to the logger for debugging
        Log.d("PhoneCallStateNotified", myState.toString());
        if(myState == Phone.State.RINGING){
         // Celebrate =D
        }
     }
    }
  };
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle icicle) {
   // Set some simple layout
    super.onCreate(icicle);
    setContentView(R.layout.main);
    /* Create a new PhoneStateIntentReceiver
   * that will pass messages to the handler h
   * as it receives Intents we make it notify
   * us below*/
    this.myPsir = new PhoneStateIntentReceiver(this,
      myPhoneStateChangedHandler);
    /* As we want to get notified on changes
   * to the Phones-State we tell our
   * PhoneStateIntentReceiver myPsir,
   * that we wan to get notified with the ID
   * (PHONECALLSTATE_RECONGNIZE_ID) we pass to him
   */
    this.myPsir.notifyPhoneCallState(PHONECALLSTATE_RECONGNIZE_ID);
    /* Register the Intent with the system. */
    this.myPsir.registerIntent();
  }
}