Dumbledore is definitely dead. But Snape is still a good guy - he knew Dumbledore was dying anyway, and to stay "embedded" with the death eaters he did what he had to do. But Dumbledore ought to join the portraits in his own office now, so perhaps Harry will be able to keep communicating with him...

JKR has said that she won't kill Harry off.

I have to say, I'm not sure I agree with some of the other posters about it being "great" children's literature. Conceptually there have been some wonderful moments, but the writing itself can be quite two-dimensional. She's also pulled some turkeys, in my opinion, because she committed herself to seven books from the beginning, she's had to engage in some plot devices and spinning out of the storylines that hasn't always worked. Order of the Phoenix was, for the most part, just wheel-spinning. It's the book she had to write in order to get to the promised seven, but it didn't really progress the over-arching storyline much at all.

I think it's more of an enjoyable romp than great literature. And its huge popularity now is neither testament to its greatness, nor to its endurability: look at hugely popular Victorian children's writers like Mrs Molesworthy. Who reads them now?

Philip Pullman, on the other hand, is a bloody good writer.