Even if you don't belong to a book club, these websites can be helpful in choosing something to read. And if you do belong to a club, here are a few places to get suggested titles as well as discussion questions.
ReadingGroupGuides.com - Blogs, polls, recommended reading, Oprah's books...it's all right on the homepage. And if that wasn't enough, the menu across the top has even more stuff, like information on starting a book club, a newsletter, and discussion guides. Some books published in the last couple of years or so may have guides in the back as well as an interview with the author. You can find similar information with this website. If you can't find a guide, there's even a link on the "Find a Guide" menu for help in making up your own questions. Nearly 3000 guides are available here, so you and your group should have plenty to choose from.
Reading Group Choices - This site has similar information but perhaps in a more user-friendly layout. One unique feature is the wine or food suggestions to go with your book. You can join and participate by sending in favorite books. The search box is right on top of the screen for easy access.
BookBrowse - There's a lot here too, from blogs to advice. You can get discussion questions and author interviews and suggested titles. You can search the site on the left or just follow the links. If you join the site, you'll have access to the magazine.
Barnes and Noble and Amazon have sections for book clubs also. (Barnes and Noble makes theirs easy to find, at the top of the homepage. Amazon requires a little searching.) Also don't forget to check author and publisher websites for biographical information and perhaps some background information and maybe discussion questions.