This is just a roundup of the Second Week of OSSEC (2WoO) posts on (or before) day 1:
Week of OSSEC: Day -2: Syngress released a few chapters of the OSSEC book, and is offering 30%.
PaloAlto Firewall Threat Monitoring Using OSSEC: @xme explains and posts a decoder and sample rules for a PaloAlto firewall.
2WoO Day 1: Crowdsourcing Log Integrity & Non-repudiation: Michael Starks discusses the idea of making hashes public to help prove logs weren't tampered with.
WoO Day 1 : Introduction: Jason Frisvold gives a quick introduction to what OSSEC is.
If I missed any, please let me know!