phpMyID is a single user (though, if you were so inclined, you could
easily turn it into a multi-user setup) IdP, or "Identity Provider"
for the OpenID framework. It's a single PHP script with minimal
dependancies. You don't need a database, you don't need to make your
filesystem writable, you don't need to download any libraries, and you
don't need to recompile PHP.

WWW:	http://siege.org/projects/phpMyID/