Meg Cabot - Shadowland

Sixteen-year-old Suze Simmons is quite used to finding ghosts in her bedroom--in fact, she sees them everywhere. Even when she and her mother move from New York to sunny, palm-tree-ridden Northern California they won't leave her alone. As a mediator--someone who must help restless ghosts settle their scores with the living before they can find peace--Suze is surrounded by needy souls who pester her for all sorts of help. Hoping to leave her irritating talent behind in order to focus on shopping and trips to the beach, Suze cannot shake a gorgeous 19th-century hunk named Jesse who refuses to leave her house, or a spiteful, vengeance-seeking ghost who haunts her high school. This is the first book in the bestselling Mediator series by the author of the wildly popular Princess Diaries titles.