I've put together a series of First Look blog posts covering Oslo, Dublin, and Workflow 4.0.
These posts include several screen shots of the new Microsoft Technologies and gives you a high level overview of some of the new features.
Check them out here:
First Look Dublin (Windows Application Server)
First Look Oslo (Quadrant and M Modeling Language)
First Look Workflow 4.0
Do not forget to check out all the great videos on these same subjects at BizTalkGurus.com media gallery.