Setting up Devise with your Rails 3 application

The following tutorial provides probably the easier and simplest method for setting up a rail 3 web app using Devise authentication that I've seen. However, I'd additionally add that under your app setting up at config/routes.rb the following:
 default_url_options :host => "localhost:3000"

 or at least you'd want to set your default_url_option to something initially valid. Otherwise, you'd get a routing error.