Charlotte & Mecklenburg County Library's Reader's Club
For a single library, this site is loaded with resources including book recommendations, monthly features, and Book Talk, their discussion board which features a different book each month. They also sport an excellent Reading Resources section.

New York Times Book Forums
The New York Times Online has a number of reading forums going on at any given time. Check out their monthly book forum.

Utne Book Club 2003
Utne Reader's online book club has laid out a year's worth of monthly reading and discussion. Good books, too. Check it out.

Salon.com Table Talk
Salon.com's book club is a mish-mash on a variety of topics. One cool feature is the ability to read through the archived discussions.

Book Chat Central
I haven't participated, but I like the look of what they're discussing in the Book Bunch - an interesting mix. Also there are a couple of specific chats - looks like murder mystery.

Literary Fiction Lovers
Their reading schedule is laid out through June, and it looks like they've got some good stuff on tap.