rails 2

  map.resources :products, :collection => { :notify => :post } do |products|
    products.resources :orders,
      :member => {
        :change_payment => :get,
        :invoice => :get,
        :pricing => :get
      }, 
      :collection => {
        :pre => :any, 
        :new => :post
      }
  end

rails 4

  resources :products do
    post :notify, on: :collection
    resources :orders do
      member do
        get :change_payment
        get :invoice
        get :pricing
      end
      collection do
        post :new
        match :pre, via: :all
      end
    end
  end