You can find some sneak preview here.
Nice name . Everything is called now with the "foundation", like presentation Foundation (Avalon). It looks like that BizTalk will have use this foundation.
Just think about:
Currently BizTalk is all about messages and persistance. What about scenarios where persistance is not required, or application business workflows (usually hosted in-memory)?
I think WWF should provide solid "foundation" for all these scenarios.