You should use and Handlers... Not so easy to implement.

//ON SERVICE SIDE
public class YourService extends Service {
public static final int SAY_HELLO = 1;
public static final int REPLY_HELLO = 2;

private int cnt = 0;

class IncomingHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SAY_HELLO:
msg.replyTo.send(Message.obtain(null, REPLY_HELLO, cnt++, 0));
break;
}
}

/**
* Target we publish for clients to send messages to IncomingHandler.
*/
final IncomingHandler mHandler = new IncomingHandler();
final Messenger mMessenger = new Messenger(mHandler);

}

//ON CLIENT SIDE

...
final Messenger mMessenger = new Messenger(new IncomingHandler()); //You can do it...
private Messenger mBoundService;

private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
mBoundService = new Messenger(service);
mIsBound = true;
try{
Message msg = Message.obtain(null, 1);
msg.replyTo = mMessenger;
mBoundService.send(msg);
} catch (RemoteException ex){
ex.printStackTrace();
}
}

    public void onServiceDisconnected(ComponentName className) {
    	mBoundService = null;
        Toast.makeText(context, "Connection GONE", Toast.LENGTH\_SHORT).show();
    }
};


public void doBindService() {
	Intent intent = new Intent("com.yourpackage.YourService");
	if (!context.bindService(intent, mConnection, Context.BIND\_AUTO\_CREATE)) {
	    try { 
	        context.unbindService(mConnection);
	    } catch (Throwable t) {}
	    // Clean up 
	    return;
	}
}

public void doUnbindService() {
    if (mIsBound) {
    	Message msg = Message.obtain(null, MESSAGE\_UNREGISTER\_CLIENT);
    	msg.replyTo = mMessenger; 
    	try{
    		 mBoundService.send(msg);
    	 } catch (RemoteException ex){
	     }
        context.unbindService(mConnection);
        mIsBound = false;
    }
}

So Sry... Im not so good helping ppl. Just wanted to share this, becouse it has been hard for me to.