I very much enjoyed "Keeping You a Secret" by Julie Anne Peters. However, it is not a positive coming out story. Nevertheless, it is a great book with a great lesbian relationship.
I second Keeping You A Secret. Also Annie On My mind by Nancy Garden is very sweet and Dare Truth or Promise by Paula Boock. Like Me by Chely Wright is an autobiography.
The "coming out" themed books I've seen are a bit dated. Most deal with poor outcomes, which were more the rule a decade or so ago. I find the hundreds of coming out videos on You Tube to be much more interesting and up to date - and, they're true stories told by the first person!
