If you would like to try an online book discussion group, try Abebooks' Avid Reader Book Club. The current book is The Curious Incident of the Dog in the Night-time by Mark Haddon. Previous choices were:
Angle of ReposeWallace Stegner
The Kite RunnerKhaled Hosseini
The Time Traveler's WifeAudrey Niffenegger
Balzac and the Little Chinese SeamstressDai Sijie
Jonathan Strange & Mr. NorrellSusanna Clarke
Life of PiYann Martel
The Reading Group Guides website is currently discussing Shadow of the Wind by Carlos Ruiz Zafon, one of my favorite books in recent years.
On the same website is a reading guide and discussion for the Big Stone Gap Trilogy by Adriana Trigiani and Water for Elephants by Sara Ruen which has been touted as the best new read of the summer.