For basically a straight up gay forum hit up Gay Life. It's free, anonymous and a relatively safe forum for gay men to chat: www.gaylife.about.com/mpboards.htm
If you want to meet some gay teens to get support about being a fag, or maybe just "make friends" you could check out Chad Boyz: www.chadzboyz.com
If you want to dive head over heals into some gay coastal escapes and attend some exclusive retreats to mingle in some potential dude orgies: www.gayoutdoors.org/forums2000/index.cfm
Offtopic, SomethingAwful, DSLReports, Genmay, and here.
pretty much most of the forums I frequent.
Offtopic is cool because it seems there is always action over there, no dead times. I go there when I am bored. Kind of the same with SA.