Grant Skinner has figured out a way to allow his Nexus One to be used as a controller for these little race cars. By tilting the phone, the accelerometer in the phone is used to make the car accelerate at a predetermined speed. If you tilt it just a little, the car will go slow. Likewise, if you tilt it all the way down, the car will go faster.
MyDroidWorld. It’s a fully functional ROM that was made from a Froyo nandroid backup from a Nexus One.