Am I Blue is a good one. It's a collection of short stories, all about gay and lesbian teens. Another good one is It Gets Better, which is a collection of essay by
LGBT teens and adults(and their allies.) Scars is one of my favourite. Annie on my mind is also a good one and I think Tricks by Ellen Hopkins has a transgendered or gay teen in it. I know Impulse by her does, although they are more about other issues faced by teenagers, drugs, depression, suicide, and cutting, than about being gay.