This Swedish vampire film, "Let The Right One In" (based on a novel of the same name), is about a young boy named Oskar, who is bullied by pretty much everyone in his life. However, a young girl named Eli moves in next door, along with her "father". Oskar soon discovers that Eli is a 200 year old vampire, trapped in youth, and that her "father" is merely a mortal servent. Oskar befriends her, realizing that she may be the method of obtaining the revenge he's always wanted.
For a look at the trailer, click
here. Keep in mind that the trailer is in Swedish. If you're interested in buying the book,
here it is at Amazon.com (released in the US as "Let Me In") in English.