I’ve been using the Devise gem for a couple apps in my recent exploration of Ruby on Rails.  It works pretty well and has a lot of great features but the documentation on how to best go about setting up administrators on it is a bit vague.  I would write up some notes on how to do it but  I’d basically be plagiarizing another post on the matter which really cleared things up for me.  Check it out: http://jonallured.com/2011/04/30/using-devise-for-admin-accounts.html