http://www.free-coloring-pages.com/online.html

you need java for that one to work i think, but it's nice they have some good selections and holiday colour books too, as well as animals.

http://disney.go.com/magicartist/coloring/

this is a disney one that has some templates you can paste into paint (or a program like that) and also has some online ones as well. my boyfriend's littles love disney and that's one they use a lot.

http://www.enchantedlearning.com/painting/

this one has lots of animals.