permanent_redirect.rb

def ApplicationController
  # perhaps in a mixin
  def permanent_redirect_to(options)
    url = case options
      when String
        options
      else
        url_for(options)
      end
    head :moved_permanently, :location => url
  end
end

def StaticPagesController < ApplicationController
  def obsolete_page
    permanent_redirect_to new_page_url
    # or, permanent_redirect_to 'url_string'
  end
end