Identity and Access Control Guide
The patterns and practices group at Microsoft has released an online guide to claims-based identity and access control. The guide is targeted at developers and architects of web services on Windows that require user-identity information. Windows Identity Foundation and Active Directory federation are the primary technologies discussed for these solutions.
The guide starts by providing an introduction to claims and a general architecture for using claims with browser and other client applications. It then goes into detail on single sign-on for intranet applications before covering federation between different business partners.
Here are downloads for both the guide itself as well as all of the contained code samples.