DHH’s OpenIDAuthentication plugin for Rails is evolving and progressing quickly. Over the weekend, David updated the plugin to no longer assume an overloaded login form.
Removed open_id? as the idea of using the same input box for both OpenID and username has died — use using_open_id? instead (which checks for the presence of params[:openid_url] by default) [DHH - Revision 6631]
This morning, Ben Curtis put up an excellent, short tutorial on using this plugin on an existing site.
It’s wonderful having the creator of Rails working on OpenID. 
The design of DHH’s plugin is small, simple and clean — it doesn’t rely on a lot of generated code like openid_login_generator and has a much cleaner abstraction on top of ruby-openid, as compared to Eastmedia’s OpenID+Consumer plugin/generator.
The barriers to implementing OpenID for a Rails site are falling quickly.