The Boo! Book by Nathaniel Lachenmeyer, illustrated by Nicoletta Ceccoli is a haunting tale. It describes how you know if you are reading a book that is haunted, and what to do if you find yourself in that predicament.
The artwork was rendered using a mixed technique: a combination of plasticine puppets, digital photography, Photoshop, and acrylics on paper. The illustrations have a beautiful surreal feel, light and airy, which makes for great 'haunting' pictures. Check out Nicoletta's website, for her other artwork.
Although it mentions to not read a haunted book on Halloween, that is the only mention of the scary holiday, so I'm leaving it in the general collection, not in the holiday area.
I'd use this story for preschoolers to 2nd graders. It's a cute take on ghosts, and not scary at all.