The "server" end-point is located at http://login.case.edu/id. Your "identity URL" is the first.last portion of your email address followed with .id.case.edu. For example, my email is email@example.com, so my OpenID identity URL is jeremy.smith.id.case.edu. For those averse to typing (like I am), you can also use your Case Network ID followed by .id.case.edu. So, I could also use jms18.id.case.edu.
If you want to try logging in with it, you can head over to Simon Willison's Weblog and, at the top where it says "Sign in with OpenID," click on that and enter <USERNAME>.id.case.edu.
A better example is logging into Wikitravel because it shows how information (such as nicknames, email address, full name, etc.) can be shared between a OpenID Provider and client. You can sign in to Wikitravel here. The information sharing part doesn't so much "work" yet. I'm getting there.
And because it is integrated upwards towards CAS, it should interoperate with all of the other "identity systems/protocols" we've integrated with CAS like Shibboleth (and, in testing, Oracle's Single Sign On, Sun's, and Google's SAML-based Single Sign-On). I may throw up some screencasts showing the effects of this by bouncing in between normal CAS-protected apps (like this blog system or the wiki), Shibboleth protected ones, and OpenID protected ones.