According to this blog post on the Windows Live Dev blog:

Beginning today, Windows Live ID is publicly committing to support the OpenID digital identity framework with the announcement of the public availability of a Community Technology Preview (CTP) of the Windows Live ID OpenID Provider.

You will soon be able to use your Windows Live ID account to sign in to any OpenID Web site!

The Windows Live ID OpenID Provider (OP) enables anyone with a Windows Live ID account to set up an OpenID alias and to use that alias for identification at an increasing number of OpenID 2.0 relying party sites-for example: Plaxo, Pibb, StackOverflow.com and Wikispaces.

I think it's just brilliant and a move in the right direction.