restful_authentication is taken from acts_as_authenticated.
Plugin details
http://agilewebdevelopment.com/plugins/restful_authentication
Most of the resources are here:
RESTful authentication at Technoweenie’s Stikipad
There is a Railscast dealing with this plugin:
http://railscasts.com/episodes/67
And a tutorial with bells and whistles:
http://www.railsforum.com/viewtopic.php?id=14216
OpenID version
http://identity.eastmedia.com/identity/show/Restful+OpenID+Authentication
Initial Announcement
restful_authentication
Step by step tutorial. For dummies and newcomers
>DYI step by step