Damian Gostomski

The Imposter plugin allows site administrators to take on the role of another user. This is useful for development and testing purposes, as well as the ability to troubleshoot user issues without needing the user password.
It will add a link for each user in the users list, which will log the administrator as that user. They’re then logged in as that user and are no longer an administrator, until they logout of the user session, at which point they’re logged back in as themselves.

Imposter

Allows administrators to take on the role of another user for development, testing and troubleshooting purposes without knowing the users password.

Functions:
<ul>
<li>Simple LogIn (one click)</li>
<li>Simple LogOut (one click)</li>
<li>Create user automatically</li>
<li>Update user’s profile with the informations that came from Identity Provider</li>
<li>Protect the user’s profile, that the user can’t modificate the informations that came from Identity Provider</li>
<li>Syncronize the LogIn and LogOut actions between the WordPress and the Identity Provider </li>
<li>If the (Apache) agent have a long update period you can choose what to do the plugin: go to login URL or LogIn.</li>
<li>SSL support</li>
<li>Rules: If a regular expression match to the $_SERVER variable’s element put the user to the group.</li>
<li>Plus plugin: Simple Group Manager – Manage the user’s groups and the group’s roles.</li>
<li>Admin page: Users / SSO Autentikáció</li>
</ul>
For more infromation please read this: http://kir-dev.sch.bme.hu/wp-opensso
If you don’t now how it’s work: https://redmine.kirdev.sch.bme.hu:8081/wiki/wordpress/OpenSSO_autentikacio (in Hungarian)

OpenSSO

Authenticate users using  Sun's Open Single Sign On service.

Imposter vs OpenSSO