There is a good thread on the Tulane board (as mentioned earlier) about gay life at Tulane. I wrote quite a bit about it on that thread. You can check it out (I think it was the Gays@Tulane one) or pm me.
I went to Tulane for a year and now go to Brown. The gay scene here is fantastic, if you are interested in knowing more.
Other schools well known for their accepting and thriving gay scenes are Oberlin, Vassar, I think Stanford, Evergreen, Macalaster....and a lot more.
You may want to put an open post on this entire section of the forum "Tell me about the gay scene at your school" and you can develop a list.
And of course if you are female than any all-girls school will have a great gay scene.
SO funny...when I was applying to college, my grandma ferociously wanted me to go to Bryn Marr (she's an alumn). But I was boy crazy at the time and was like heeellll no. Well, things have changed a bit...though she doesn't know it. She was giving me crap for not going to Bryn Marr over thanksgiving, and I was trying to explain why I decided against it originally. And I was just thinking this is SO ironic.