Microsoft just released a new feature set on top of Access Control Service (ACS).  It is currently in “incubation” in AppFabric Labs.  The Azure Labs are charge-free developer previews of features.  They should eventually move to “production” with charge patterns.

You can see a quick (5 minutes) demo of it on Wade Wegner blog’s.  Wade is a Microsoft Technical Evangelist for the Windows AppFabric.

The take away for me is that among key new features is an integration with ADFS 2.0.  ACS seems to basically act as a proxy to other identity providers and simplify integration.

It sounds very promising!

[[UPDATE]] There is also a good and informative presentation on channel 9.