I just found this link today and thought I'd share. It's called "Gay-Themed Picture Books for Children" and has lots of gay&lesbian-friendly children's books that I've never seen (and of course the usual suspects too).
Great list. We especially like Emma and Meesha my Boy around our house, because she's got two moms, but it's not the main point of the book... it's learning to be kind to the cat. Plus it's got a nice pattern and rhyme scheme.