These are cellbots, if you couldn't think of any reason for getting yourself an Android yet, here is one.
The communication is done over serial commands out of the USB port on the bottom of the phone
This is a very nice project as these guys are actually making the robots communicate with each other and using the accelerometer in another android phone to drive the robot around. (build that into a car ;-)
The phone as a controller makes this robots have very impressive features:
Highlighted functionality includes:
* Voice recognition to speak to your robot
* Text-to-speech so your robot can speak back
* Compass orientation to point North, East, South, West, or any degree in between
* Remote control commands for forward, back, left, right, and stop
* Audio recoding to use the phone's mic to record sounds
* GPS to acquire the phone's location and speak the city and state
* XMPP Chat to send chat commands to the robot
The code is build around the android scripting environment, using python so writing your own functionality must be very easy.
Cheap hardware and a phone make a great robot.
Sounds good? More info at cellbots.com