The WordPress OpenID plugin lets visitors to a Wordpress blog quickly register, login, and leave comments using their OpenID Identity. Says it's designed for WP 2.0.3 to 2.1, but may work with 2.3.
Wordpress OpenID PluginView Post
Subscribe
Enter your email address below to receive updates each time we publish new content.
Allow users to use OpenID to interact with your blog with OpenID WordPress plugin