I created a tutorial for Unity last night. I figured I would share some knowledge I've gained along way, mostly from other contributors on the forum. This tutorial will have you up and running in 20 minutes with a fully driveable vehicle, full on physics and fully tweakable settings. You could use this to create a racing game, a stunt game, or just vehicles for your game. Thought I'd give back to the community a bit.

http://www.youtube.com/user/PolyNurb#p/u/0/21zuMIsy2GM