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.
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.
Our book club tends to be a social gathering as much as a discussion group. Usually each meeting entails wine, food and, of course, the book. So we coordinate our reading, our food, wine all through Qlubb. It's just an easy way to manage each meeting and attendance. It's super easy and free.