The Lambda Literary Awards include a Children's and Young Adult category. Past award winners are here: //www.lambdaliterary.org/awards/previous_winners/paw_2004_2006.html.

The Human Rights Campaign has several annotated bibliographies listed here http://www.hrc.org/issues/parenting/schools/7839.htm

That should give you quite a bit, but if I think of more sites I will add them.