This is a little project I threw together yesturday.
Taking a basic cheap as chips R/C toy car, I replaced the R/C circuit with a servo controller and
bluetooth modem. I also changed the steering from a DC motor which gave 3 states; centered,
full left and full right, to a 9g servo giving more precise control and a larger lock angles.
The app sends the steering angle and the speed value, calculated from the accelerometers,
over a bluetooth SPP connection.