When I posted my wheel collider demo on the Unity forum I got some good feedback. This post includes an updated scene and script.
The finished Unity Wheel Collider scene in the Unity web player.
The wheels are fixed so they appear to spin and steer, reverse gear is added and the complete updated script provided with commentary.
A simple vehicle control script is explained and added to our wheel collider project.
I explain how easy Unity scripting is for non-programmers.