3-D Chess Federation - A place for those who are especially interested in 3-D (by contrast to ordinary 2-D) chess variants. Offers information, rules, downloads, photos and diagrams. - http://www.3dchessfederation.com
The Chess Variant Pages - Comprehensive, general site with downloads, rules, information, histories and links for a large number of chess variants. - http://www.chessvariants.com
Chess Variant Applets - One player chess variant java applets of a large number of games but not of high difficulty. These works of Dr. Ed Friedlander recently became dual-published as a section of The Chess Variant Pages as well. - http://www.chessvariants.com/play/erf