First Grave on the Right by Darynda Jones

Forget the vampires. Charlotte "Charley" Davidson is the "grim reaper." Helping to enable people to pass over to the "other side," she poses as a Private Investigator to cover the conversations she has with dead people, usually ones who have been murdered. To complicate things, she seems to have a thing for a really "hot" supernatural being. Interesting concept. An ok read if you like this sort of thing.