Well, I remember seeing some TV program with an interview with her and she said she has the epilogue of the final book written (she was actually holding a folder that she said had it inside it), so she probably knows whether or not Harry dies. Besides, she's writing the final book now... She'd be in trouble if she didn't know how it was going to end.

As for my thoughts... I think Harry's gonna bite it. It's my personal belief that he is a horcrux himself, or if he doesn't die, he'll lose the scar somehow.