BookMovement - A book club planner. Find out what other book clubs are reading and raving about. Use the planner to send email reminders and book discussion guides to your group members.
Book Muse - Provides weekly reviews for various book genres, as well as offering recommendations across the spectrum.
LibraryThing - A social network for readers and writers.
Book Discussion Center - Links to online book discussions, publishers guides, guides for selected titles.
Library Booklists - "This website consists of four sections: original booklists on various topics, primarily but not entirely focused on themes, places, characters, and plots of crime novels; annotated lists of other booklists, primarily but not entirely focused on fiction, for adults, kids, and teens; a growing calendar of authors' birthdates, organized by month, with links; and some resources for reading groups (discussion questions, recommended books, how to start a group, etc.)."