Ok:
It moves, But its kinda weird. the ball moves but i think its the gyroscope not the accelerometer. It works in the sense if i move my phone in a 360 degree movement the ball follows that pattern, i oppose to the accelerometer, Where if i tilt the phone left, the ball would move left and vice versa with right up and down :)
they both move on the 3gs(Have not tested with 4s yet) But its not easy to control, I dont get it.. Second link was better but first link as the first link i kept on moving off the screen...