Do keep in mind it's easier to color when the artist has already included shading - just a note.
I used to periodically check out
http://www.fur.com/~almackey/tutorial/ for info/help on photoshop coloring (I think I found the link back on the original Process boards or something, not sure). Though it's not my thing, for those who are also interested in TF, the guy who runs the page is a furry artist.
Anyway, just thought I'd share the link.