Emma was recently interviewed by WizardUniverse and they have posted the interview. (I posted their interview with Dan earlier today)  They will also be releasing an interview with Rupert.

Do you think the fans of the book will find “Half-Blood Prince” to be a faithful adaptation?
WATSON: I hope so. I think we’ve stuck as close as we possibly can without making a ten-hour movie. We’ve never had that complaint before, and I personally am such a big fan of the books. I’ve read them each of them three or four times so I think that’s a really good focus for us.