Recently in my (physical) mailbox: SELinux by Example by Frank Mayer, Karl MacMillan, David Caplan. The most recent and up-to-date book about SELinux I know about, written by some of the most involved and knowledgeable people in the field.
From what I've read until now it seems to be a really in-depth and easy to understand introduction, and what's more important, it covers the practical aspects of how you use, configure, and administer SELinux in real deployed systems.
This should make an interesting read...