Retrieve incoming call's phone number in Android

I would like to retrieve the incoming call's phonenumber and do something with it like the do in http://blog.whitepages.com/2009/02/27/caller-id-by-whitepages-a-new-android-app-that-puts-telemarketers-on-alert/

Could you please help me because I can't find any information about this. Where do i start and how do i get hold of the phonenumber?

Ok so currently my code looks like below. When I place the call the CustomBroadcastReceiver catches it and the log message is printed out. I can retrieve the telephone number from the bundle. But! I can't get hte CustomPhoneStateListener to work. As you can see I have registered my customPhoneState listener to the receiver but the log message never get's printed out from the CustomPhoneStateListener class. What am I my missing here? Is my thinking correct?

<receiver android:name=".CustomBroadcastReceiver">
        <intent-filter>
            <action android:name="android.intent.action.PHONE_STATE" /> 
        </intent-filter>
</receiver>

</application>
<uses-sdk android:minSdkVersion="5" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_CONTACTS" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

public class CustomPhoneStateListener extends PhoneStateListener {

private static final String TAG = "CustomPhoneStateListener";

public void onCallStateChange(int state, String incomingNumber){

    Log.v(TAG, "WE ARE INSIDE!!!!!!!!!!!");
    Log.v(TAG, incomingNumber);

    switch(state){
        case TelephonyManager.CALL_STATE_RINGING:
            Log.d(TAG, "RINGING");
            break;
    }   
}

public class CustomBroadcastReceiver extends BroadcastReceiver {

private static final String TAG = "CustomBroadcastReceiver";

@Override
public void onReceive(Context context, Intent intent) {
    Log.v(TAG, "WE ARE INSIDE!!!!!!!!!!!");
    TelephonyManager telephony = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
    CustomPhoneStateListener customPhoneListener = new CustomPhoneStateListener();

    telephony.listen(customPhoneListener, PhoneStateListener.LISTEN_CALL_STATE);


    Bundle bundle = intent.getExtras();
    String phoneNr= bundle.getString("incoming_number");
    Log.v(TAG, "phoneNr: "+phoneNr);

}

Use PhoneStateListener. It has an onCallStateChanged handler; one of the supplied arguments you'll get is a String containing the incoming phone number.

Your overridden method in CustomPhoneStateListener should be called onCallStateChanged() (and not onCallStateChange()).

This would have been spotted by the Java compiler if you would have had the @Override annotation, like you have for onReceive().