There's one at my school, it's called Common Ground. I never cared for it because it's too emotional. I guess it's great for people that are still having struggles with their sexuality, whether it be coming to terms with it or stop caring how others view it, but I'm not in that position so it doesn't click with me.
My school has one, but I'm not in it because the school environment is very friendly and comfortable for a homosexual anyways. And it's very small and insignificant but the leaders put a lot of pressure and emphasis on attending meetings and volunteering to help sell things to raise money for the group. I have better things to do