Luna by Julie Anne Peters
I've liked the other two JAP books I've read...teen chick lit about cliques and lesbian dalliances and the like (the latter somewhat similar to CINECAST!ing Amal really). This one is focused on girl whose brother is transgender (and thus her sister). I'm about 1/3 in and I think Twilight has ruined other teen chick lit for me. Say what you will about Twilight, it is an epic and instant classic of the genre. The gender stuff is fine but listening to the protagonist stress about boys and such is painful in comparison to Twilight.