Users join a group of 6 and rotate books each month...so you contribute your own book and read 5 others that are sent to you each month. It's pretty cool...and it's free. So far I've read some great books.
I hype this site pretty often - it's an e-mail book club (actually, a dozen of them, and you can sign up for as many as you want) that makes weekly selections and e-mails you daily excerpts. It's a convenient way to sample books, and I've found a lot I wanted to read further after getting that taste.
Go to any small, independent bookstore and you are likely to find the most current issue of the Booksense newsletter. Each month, a list of book recommendations is compiled, based on recommendations from independent bookstore employees. There are also specialty pick editions that focus on a specific theme or genre. These books might not all be on the best seller lists, but they are wonderful books nontheless.