I know City of Heroes has a free standalone costume creator.
Different versions of heromachine at HeroMachine 2.5, Superhero Generator, Create a Hero UGO.com - UGO.com
Fábrica de Heróis is pretty cool but it takes a little bit to figure out the controls.
Storn A. Cook Illustrations is my buddy Storn Cook's website. He also has a thread on the boards here for even more art.
deviantART: where ART meets application! has a LOT of cool artists but will take some searching.
I made one through HeroMachine and then I discovered I had an old picture that I planned to use a while back for a different game.