Reposting this topic here as well as the Footwear forum as many of these rendering technique are also useful for non-footwear PS rendering, I know not everyone checks the footwear threads.
Footwear Rendering Tutorial
http://www.firstpullover.com/2007/01/fo ... orial.html
First Pullover, footwear design/development blog
I was planning to also post it here, but there are just too many images to do it easily (40+) and uploading all through flickr is a pain. Please see the blog, but feel free to comment and add anything here.
If you have any specific hints, questions, etc. throw them down here and ill try to address them in the tutorial.