An interesting post on the Google Code blog:

“Haptic feedback has been added to the finger down and up events triggered when a keyboard button is clicked. These events have been adapted to create a fingertip-over event which is fired when the finger moves over any button in the interface. When the fingertip-over event is triggered, a 1-beat smooth 70ms high intensity Tacton (2) is presented using the iPhone’s built-in rotational motor.”

I played with some haptic feedback devices at Mobile World Congress in Barcelona last month and was really disappointed. The vibration comes from somewhere in the back of the phone — from a specific location where the vibrating buzzer is. In other words, the haptic feedback comes from a location not associated with the area with which you’re interacting. For me, it was a distraction rather than a feedback

I love the concept, but in practice it’s not there yet.