Impossible Creatures

2 Clan
Provides downloads, screenshots, and a member list.
http://www.freewebs.com/ic2clan/

Down Right Deadly Clan
Has tips and screenshots.
http://www.freewebs.com/rare_hunter/

GRC
Offers hints and tips.
http://www.geocities.com/grcwebsite/

Impossible Creatures Center
News site covering iCreatures, includes forums and exclusive screenshots.
http://www.strategyplanet.com/sigma/

The Impossible Menagerie
A modification project to create new animals.
http://www.geocities.com/alex_j_holt/page3.html