I had the great pleasure of co-authoring an article with my teammate Vittorio Bertocci on the September LABS release of the Windows Azure AppFabric Access Control. This article, entitled Re-Introducing the Windows Azure AppFabric Access Control Service, walks you through the process of authenticating and authorizing users on your Web site by leveraging existing identity providers such as Windows Live ID, Facebook, Yahoo!, and Google. Specifically, this article covers:
Outsourcing Authentication of a Web Site to the Access Control Service (ACS)
Creating the Initial Visual Studio Solution
Configuring an ACS Project
Choosing the Identity Providers You Want
Getting the ACS to Recognize Your Web Site
Adding Rules
Collecting the WS-Federation Metadata Address
Configuring the Web Site to Use the ACS
Testing the Authentication Flow
ACS: Structure and Features
Sounds like a lot, but hopefully you will find the article straightforward and helpful.