Once upon a time I wanted to be a comic book artist, so most of my influences are comic and cartoon artists. These sites include the works of a few of my favorites:
Here's a fan site dedicated to Bruce Timm
This site includes original art by Jonny Quest
's creator, Doug Wildey
This is a modest page devoted to one of the best comic artists I've ever seen, Michael Golden
And another devoted to the
best comic artist I've ever seen, Wally Wood
Unfortunately, none of the above come with How-to pages, but I'm mostly self-taught and try to learn by example anyway, and all of these artists provide great examples.