Lean Forward -> Drive Forward
Lean Backward -> Drive Backward
After seeing some other designs online for 2 wheeled robots, I went "hey that looks easy, I could do that, no problem."
Turns out, its a little harder than expected.
I made a little animation showing some of my first ideas, but it wont embed, so guess you'll just have to click it...
LINKS:
http://www.tedlarson.com/robots/balancingbot.htm
http://www.geology.smu.edu/~dpa-www/robo/nbot/
http://www.cs.ut.ee/~toomas_l/linalg/matlabap/control/control12.html