ruby script/plugin install http://craz8.com/svn/trunk/plugins/authenticate_as_remote_user/

rake

rake test:plugins PLUGIN=authenticate_as_remote_user

Include RemoteUser into controllers
Example:

class ApplicationController < ActionController::Base
     include RemoteUser
     ...

Implement the find_user method to load your user model
Example:

class ApplicationController < ActionController::Base

	include RemoteUser

	def find_user(remote_name)
		User.find_by_name(remote_name)
end

Imeplement the access_denied method
Example:

def access_denied!
     redirect_to access_denied_path and return false
end

Implement before_filter for login_required for actions you want to protect
Example:

class SomeController < ApplicationController
	before_filter :login_required, :only => [ :update, create, destroy ]

Optionally implement remote_property_name to match your Apache configuration
Example

def remote_property_name
	"HTTP_REMOTE_USER"
end

There is currently no advanced documentation for this plugin.