Plugin to integrate WordPress or WordPressMU with existing CAS architectures. Based largely on Stephen Schwink's CAS Authentication plugin.
I've only tested it with the 1.0 release available from ja-sig.
Users who attempt to login to WordPress are redirected to the central CAS sign-on screen. After the user's credentials are verified, s/he is then redirected back to the WordPress site. If the CAS username matches the WordPress username, the user is recognized as valid and allowed access. If the CAS username does not exist in WordPress, you can define a function that could provision the user in the site.
There is none.
You might be thinking of Stephen Schwink's CAS Authentication plugin. This plugin would be a lot different if I couldn't lean on Stephen's excellent work. My primary reasons for branching (under the the terms of the GPL) were that I wanted it to work better with WPMU and needed an easier way to hook-in functions to provision users and wanted to do that while also making it easy to upgrade using SVN (thus the config file).