This is basic stuff and many people have probably seen it already. But I love how Carles lays it out. This is what printed 3d party books would be like if they had color. Going through his scene light-by-light makes it extremely easy to follow.
http://www.3dluvr.com/content/article/42
The rest of his site, with other tutorials:
http://www.3dluvr.com/carles/home_eng.htm
(I've forgotten whatever basic html I ever knew, sorry.) -govinda