Voki - animated/talking avatars

Build Your Wild Self - lots of fun!

Doppel Me!

Read The Words - create text to speech avatars. 

Be Funky - Upload photos and change them to look like sketches, paintings, and more.

Face of the Future - not really an avatar creator, but the resulting image could be used as such

Hero Factory

Marvel Create Your Own Superhero

MagMyPic - Turn your picture into a custom magazine cover

Simpsonize Me! - Turn yourself into a Simpson's character