Form Posts Across Different Controllers?

I have a basic, basic question about form posting across different controllers. I think I'm having a fundamental problem understanding html forms, while ruby I understand fairly well.

If I have on my "item" "show" page:

<% form_tag '/users' do %>   <%= hidden_field_tag "id", @item.id %>   <%= submit_tag "Add Item" %> <% end %>

and in my "users" "show" controller I have:

def show flash[:notice] = params end

I just want some sign that my items controller has passed an id in the hash to the users controller. For some reason this does not work and only "actionshowcontrollerusers" shows up in the hash. If I could just get the item ID from the items controller, I'd be set, but for some reason I'm not able to transfer data between controllers...

PLEASE help. Thank you.

David