Further to that round table I did on SF Signal, here are a couple of places where you can find out what is going on in YA SF&F.
The YA SF&F blog is run by Aurora Celeste, who is a member of the target audience.
The Intergalactic Academy is run by two adult writers, Phoebe North and Sean Wills, who write YA SF.
All of them know far more about the subject than I do, as do Gwenda Bond, Tarie Sabido, Tehani Wessely and Malinda Lo.
Proxima publish YA SF – one of my friends (who will remain nameless to keep this comment “neutral”) has had his YA SF published there… see proximabooks.wordpress.com for details.