gistfile1.txt

before_filter :find_user, :only => [:show, :edit, :update, :destroy]

def find_user
  id = params[:id] == 'current' ? current_user.id : params[:id]
  @user = User.find(id)
end

// and in your application controller

def current_user
  if cookies[:auth_token] && !cookies[:auth_token].blank?
    @current_user ||= User.find_by_auth_token!(cookies[:auth_token])
  else
    @current_user = nil
  end
end