Some of the other plugins in the wild were more complex than I needed, so I wrote my own.
This plugin is basically just a generator. You can delete the plugin once you run it.
script/plugin install git://github.com/seven1m/simple_restful_openid.git script/generate simple_restful_openid
To sign in, browse to /session/new
Edge Rails or Rails 2.1+
Copyright © 2008 Tim Morgan, released under the MIT license