There's not a whole lot out there right now but what is looks pretty good. Here are a few links:
YA Book Central: http://www.yabookscentral.com/component/content/article/25-info/10186-this-months-giveaways. Their website says they'll be adding more as the month goes on so check back weekly. Also, I've started Let the Sky Fall and it is awesome!
Goodreads: http://www.goodreads.com/giveaway/tag/ya?id=ya. They have tons so scroll through the pages and see what interests you.
Pulseit: http://www.pulseit.com/. I discovered this one from Twitter. Just sign up with their website and you can read books for free! They have a different one every week or two. (This is how I'm reading Let the Sky Fall)
Literary Rambles: http://www.literaryrambles.com/2013/04/erin-bowman-interview-and-taken-giveaway.html. Love this site! They are very generous with their giveaways.
Good luck! I hope you win something!