From Lawrence Liu's Blog http://blogs.technet.com/lliu/rss.aspx
“This white paper describes features that are included in Windows SharePoint Services SP2 and SharePoint Portal Server 2003 SP2. It also provides best practices and guidance about how you can architect your solutions considering the current and future versions of SharePoint Products and Technologies.“
The page looks pretty informative on what you features you got with SP2. It even distinguishes between WSS and SPS which should make some people happy.
Now it seems that you can get the latest KB articles delivered right to your feed reader of choice. Pretty cool. I have already subscribied to the SharePoint Portal Server articles. Unfortunately there isn't a feed for WSS yet.