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.
The Bookshelf at Mommy Track'd has book reviews as well as a comprehensive list of reading recommendations all of particular interest to working moms. You will find Books About Balance, See Mom Work Books (featuring kids books where the mom character works), Working Mom Fiction for your Non-Existent Free Time, The Anti-Princess Reading List for kids and more.
Here's their blurb from the home page:
Have you ever wanted a better way to:
* see what your friends are reading?
* keep track of what you've read and what you'd like to read?
* get great book recommendations from people you know?
It's not just a place to list the books you read, but a way of comnparing books with friends, finding new titles, and just general social networking through books. I haven't used it a lot yet, but I like the idea!