Some people have found this page using AltaVista or Yahoo search for "gay mathematicians". (How do I know - most Web servers allow you to monitor use of the links pointing to your page, although it is customary not to monitor who is using them, and search engines create the links.) I've tried it, and while this search yields my page, I did not manage to discover anything else which would be relevant among the tons of produced links.
Instead use HotBot search engine with the same pattern, and you will get plenty of useful links - I include some of them below.
(Remark: This was written long before Google, obviously, in mid-90s, when it was relevant. I just don't want to delete this paragraph. This page is more of a historical interest now, as I have not tried to maintain it for quite a while. However, I've just cleaned up all the links below and all the active links work again. Also please let me know, if there are new links I should include --- April 2005.)