I've been working with a new Workflow technology that Microsoft is planning to announce - and demonstrate heavily - at PDC. However, if you're not registered to attend PDC (and it's sold out!) then you can find out more by viewing the Week of Webcasts; in fact, I'd suggest you add Paul Andrew's blog to your morning read, as he's the the Technical Product Manager.
As soon as the announcement is done and I get back from PDC I'll have a new toy to post for everyone that gets beta bits at PDC.