A few days ago, I mentioned ottobib. Since then, Ben Tucker has brought to my attention bibme.org :"a similar automated bibliography generator. In addition to allowing for automatically citing books, BibMe supports the same for a bunch of other types of sources and lets you download the resulting bibliography as an RTF document."
bibme seems to support bibliographies (in the three main formats: APA, MLA and Chicago) for books but also for journals, magazines, websites and films.