In the end of this month, Yahoo will start beta testing for OpenID 2.0 support on all of their web application. By combining Yahoo ID and OpenID, they will have greater potential value in the future. As you might already know, Yahoo used their Yahoo ID as a global identifier on all of Yahoo's service. By using OpenID as the global identity as the gateway and then after it has been authenticated, Yahoo servers will add Yahoo ID session, thus users can browse Yahoo's network using an OpenID. Nice...
You can start upgrading your account on Yahoo's OpenID site