http://www.atitd.net Fansite with tech tree, official forums, news, guides, interviews etc
http://www.atitd.info Fansite with tech tree and maps (now redirects to info.atitd.net, where everything from atitd.info has moved with the departure of Devalin)
http://www.mihe.org/ The Friends of Mihe. A non-tech fan site. Daily Egyptian life stuffs. Home to many pictures of flowers, beetles, and sculptures.