Name of the site: 
Mounting Animation Cels written by Kenneth 
Allred. 

URL: 
http://users.animanga.com/kallred/FrameIt.html

This is the page where I got the bulk of my 
framing knowledge when I was starting out. It's 
clear, simple and darnit, it's even got spiffy 
animated gifs illustrating each step of the 
framing process. 

Hope this helps!
-MeganD.