Zermatt is a set of .NET Framework classes; it is a framework for implementing claims-based identity in your applications. This can be used in any web application or web service that uses the .NET Framework version 3.5.
Zermatt helps building externalized authentication capabilities for "relying party" applications and build custom "identity providers" (STS).
Zermatt beta is avaialble to download from here.
Zermatt also requires .Net 3.5 to be installed. It has been verified on Windows 2K3 SP2 with IIS 6.0 and Windows Vista SP1 and Windows Server 2008 with IIS 7.0.