For our project we made a little remote control car. We used a DC motor with an H bridge and programed with the arduino. The vehicle uses two wheel drive to drive, turn, reverse, and turn in a circle. It is all pre programmed to perform a series of movements.
Here is the diagram about how to set up the H bridge:
Also there is a handy tutorial from ITP about setting up the H bridge with DC motor.
Our group: Natasha, Chris, Niki, Annelie, Xing