This site is best if you're in the mood for browsing, but it's good browsing if you're looking for a book that's not only a good read, but a good source of discussion material for a reading group. Perhaps this site's best feature are the multiple categories. Click on a subject and get info on dozens of tried and true group reads.
While this site is fun to browse, it's even more useful as a source for reading guides. Click the reading guide tab for links to hundreds of discussion guides. Scroll further down the page for great advice on running a group and contributing to discussions.
Whether you're browsing or looking for info on a specific work, this site is a fabulous resource for fiction lovers. New reviews are constantly being added and the newsletter offers a handy way to get the scoop on the latest releases whether you're looking for a group or individual read.