National Gay and Lesbian Task Force (NGLTF)
http://www.ngltf.org/
NGLTF is a leading progressive civil rights organization that, since its inception in 1973, has been at the forefront of every major initiative for lesbian, gay, bisexual and transgender rights. They're at work at national, state and local levels, combating anti-gay violence, battling Radical Right anti-gay legislative and ballot measures, advocating an end to job discrimination, working to repeal sodomy lows, demanding an effective governmental response to HIV and reform of the health care system and much more.