A quick scan of the Web discovered the resources identified below; perhaps they complement the excellent Art of the Review podcasts http://networks.h-net.org/node/84048/pages/88574/the-art-of-the-review . If you have others to offer, please send them along.
How to Write a History Book Review – University of Iowa
Writing a History Book Review -- About.com
Book Reviews – Queens College, NY
Book Reviews – George Mason University