This is one technique I have only attempted once (didnt come out too good). I always wanted to learn the basics of this. There are a few site which show you step by step. I will try to dig up the addys so you can all benefit from the tutorials.
I will not be around this weekend for this one.
Good luck to you all. I am really interested in seeing this one for sure.
Here is the link.
Object Source Lighting :: The Basics*-*BrushThralls.com
I hope this helps you all in your efforts.