Yes, that back wheel rotates on its own. The inspiration for the entire robot was basically a forklift, because it has two wheels in the front and one in the back, and an arm that raises and lowers. We haven't finished the arm code yet, but here is a video of our first drive test. This was very rough, but it's a lot better now.
Video on YouTube:
http://www.youtube.com/watch?v=Jde7YWrRe4s