hello...
this is my very first post in this site...and I think I love it.
I didn't read all the answers to your inquiery...but here is a link to a good tut for headlights :
http://www.3dcar-gallery.com/tutorial/less02.htm
It is not so detailed..I mean it is a simple old fassioned light..but I hope it works for you bud..and thanx for the auther
That one was already posted.