It's called Midnight Mass, and it's by a guy named F. Paul Wilson. I'd never heard of him before I read this book, but he's written a motherload of other stuff, too. I may have to start looking for more of his books now. :)
I would recommend Midnight Mass to any vampire fan, but a specific recommendation goes out to Stephen King fans who've never read any other vampire novels, but want to branch out.
With all that being said, I need to go and get back into bed (I've been sitting up reading). I have to get up in six hours and fifteen minutes.