For now, it's only the head in a custom-made R2-D2, but soon the whole astromech will obey the orders of an iPhone, including the possibility of firing sounds and send text to its head displays.

For now he only controls the servo and dome motor with the accelerometer, as well as touchscreen controls. His plan is to have the whole thing controlled using an iPhone interface that uses both the accelerometer, as well as buttons and gestures on the touchscreen.

Although this one is not controlled by the iPhone, here's another video of Glenn's R2 just humming along his living room.

[Glenn's Astromech via Make]