The ALA site has a lot of information on Banned Books Week, including...
ALA's list of the Top 100 Banned/ Challenged Books from 2000 to 2007
Both FaceBook and MySpace have pages for Banned Books Week
The American Booksellers Foundation for Freedom of Expression site has a section dedicated to Banned Books Week, which includes a nice listing of books that have been challenged or banned along with the stories behind the challenges/ bannings.
The Forbidden Library also has book listings, information on why books were challenged/ banned, quotes on censorship, and links to other sites addressing the topic of banned books
The Banned Books blog is dedicated to reading and reviewing banned books.