Microsoft's proprietary passport network is now known as the "Windows Live ID Service" but it's still just as proprietary and locked in, and it's only real improvement is support for CardSpace for authentication.
The Microsoft Code Name "Zermatt" is a framework targeted for .Net developers to help them to build claims-aware applications to address today's application security requirements using a simplified model that is open and extensible and can improve security. Developers can build externalized authentication capabilities for their applications and build custom "identity providers", often referred to as Security Token Services (STS).