The fifth Snort Report -- Snort Rules -- has been posted. In this article I talk about what Snort rules really mean. I discuss how to get rules from Sourcefire and Bleeding Edge. I don't plan to explain the rules in a feature-by-feature manner because the Snort Manual does that already.
Also, Snort 188.8.131.52 is available. Here are the release notes.
If you missed the earlier editions they are linked at the top of the list on my company research page.