"Passport will be adding support for WS-Security in 2003 so that it can securely interoperate with other systems that support the WS-Security standard. By integrating these standards into its products and services, Microsoft will create a broad-based solution that will enable a host of federated security scenarios. In some of these scenarios, Passport becomes a node in a broader federation network." [MS via Scott Loftesness]

What looked like a possibility 6 months ago, is almost a certainty today. The statement quoted above taken together with the fact that Liberty Alliance spec are built on SAML and with a promise of WS-Security supporting SAML is just another indication that we will hear something about Liberty working with Passport sometimes during the next year.