The POD people blog is seeking 'occasional reviewers'. This not-very-onerous position gives you access to the review request yahoogroup. If you see a book you would like to review you reply to the author directly and CC the group to let others know the book is taken. We would then hope to see a review posted (or forwarded to me for posting) within three months.
Occasional reviewers have no participation requirement and, like the rest of us, receive no compensation other than review copies and a linked byline. If you would like to join our merry band please send an email to email@example.com with a sample or link to a review you have written (or other evidence that would lead me to expect that you are capable of writing a book review).