Seems like most Christian authors use Facebook, their website or Twitter (maybe all three) to invite folks to review their books, often as part of a "blog tour," where there's a specific week for everyone to post their reviews online and spread the word about a new book. Generally you get a free copy of the book for agreeing to be part of the review process.
Looks like Tyndale's taking that idea a bit further and creating their own panel of bloggers to review their books and other products. I applied yesterday and got an email this morning saying I'm in. Yay!
If you're interested in joining, go to Tyndale's Media Center  and check it out!