www.booksneeze.com
Christian books
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Litfuse Group
Waterbrook Multnomah
Christian books
Navpress
Christian books
Harper Collins First Look Program (temporarily not available)
You don't have to be a blogger to be involved in this one. I did this one for a while and received many very good mainstream books from them. You can choose your genres that you're interested in. I reviewed books like: Football Hero by Tom Green (very good even if you're not into football, i think I cried once or twice), Ever by Gail Carson Levine, Seeker #1: The Quest Begins by Erin Hunter and many others. The message on the First look page says they are on Hiatus while they "create and even better book program"
As I find more I'll list them. I'm also looking for main stream publishing companies that have blogger book review programs that aren't necessarily christian books.