OpenID ist ab der Drupal Version 6.0 in das Core-System integriert und muss nicht mehr per Plugin nachgeladen werden:

OpenID support is built in, making it even easier for your visitors to become a member of your site. OpenID is a free and easy way to use a single digital identity across the internet. With OpenID, login to all your favorite websites and forget about the online paperwork.

Quelle:
http://notizblog.org/2008/02/14/drupal-60-with-nativ...