The website at openidsamplestore.com was built to demonstrate how a website that already allows users to login can help those users (and new users) leverage OpenID to login.
The initial version of the API will use the OpenID 2.0 protocol to enable websites to validate the identity of a Google Account user, including the optional ability to request the user's e-mail address.
This summer MySpace announced that it would implement OpenID and a number of new user data hooks for developers to build mashups with. That announcement was made in July and there's been no MySpace OpenID seen in the wild...until now.
Wanna know how we know MySpace is going to support OpenID soon? Dig into the HTML of your account page and you'll find a URL that references "https://api.myspace.com/openid".