Right now I'm working on two novels, one a fantasy and the other a suspense/romance/mystery thing. And, they both have prologues. I've debated about using prologues on both of them and came to the decision that, yes, using a prologue on them was fine. I decided my prologues did give the reader info that was needed, that would enhance the story, make it a bit better for the reader just starting the book.
Then, as I got more along in the revising process, I came to the conclusion that I really didn't need a prologue on the fantasy novel after all. The info I give out can be woven in later. So, now I've got to get rid of the prologues and do some tweaking.
What about you? How do you feel about prologues? Do you read them or just skip over and start with chapter one? Have you pondered the issue of using a prologue in your own writing and if so, what did you decide?
Here's a great article on prologues.