I heard from several people that while the information for SharePoint development was great at PDC, that it was not obvious what was WSS vs. the other investments on top of WSS. That's b/c we haven't made any final packaging and licensing decisions. So if you are a -little- confused, that's why! Somethings are very clearly platform while others may not be super clear in how it will be packaged... at this very moment, we're discussing our investments more "functionally" - i.e. web content management :services", for example. At this point, if you're a developer, don't worry about how that will we delivered... just be excited that we're doing some amazing things! I know it's easier said than done, but we don't release packaging and licensing information until much closer to release.
For developers who want to get their hands on the technology, beta is scheduled for first half of 2006.