To dig deeper into SELinux, there are a variety of technical reports, FAQs, and component documents available. Here are a few places you can try:
FC3 SELinux FAQ (fedora.redhat.com/docs/selinux-faq-fc3) — Provides information specific to the SELinux implementation in Fedora Core 3.
Getting Started with SE Linux HOWTO (www.lurking-grue.org/GettingStartedWithNewSELinuxHOWTO.pdf) — Provides helpful hints for getting started with SELinux.
SELinux Documentation (www.nsa.gov/selinux/info/docs.cfm) — This site provides links to published papers, technical reports and presentations related to SELinux.