First Grave on the Right, by Darynda Jones

An entertaining bit of fluff, featuring Charley Davidson, a private investigator with a part-time job as the grim reaper.  She seems a bit more of a ghost whisperer than a traditional grim reaper, as her role seems to be to help dead people with unresolved issues go into the light  through her.  Recently her life as been complicated by the spawn of Satan, who protects her from homicidal attacks as well as from his dad, who seems to want her dead as well.  Silly, but enjoyable.