This site is connected to several commercial discount booksellers. It does have good information about how to start and run a book club. It also has links to other sites that feature reading guides.
Book Group Corner http://www.randomhouse.com/resources/bookgroup/ List of recent publications with reading group guides
Random House Reading Group
Monthly group of reading guides. Also included are tips for Reading groups.
Reading Group Guides
Search hundreds of publishers’ discussion guides by author, title and category. Includes author interviews, short biographies and ideas for book groups.