<% form_for :product, :url => { :action => :create } do |form| %>
  <%= error_messages_for :product %>
  Title:       <%= form.text_field :title %><br/>
  Description: <%= form.text_area :description, :rows => 3 %><br/>
  Image url:   <%=form.text_field :image_url  %><br/>

  <fieldset>
    <legend>Details...</legend>
    <%= error_messages_for :details %>
    <% fields_for :details do |detail| %>
      SKU:          <%= detail.text_field :sku %><br/>
      Manufacturer: <%= detail.text_field :manufacturer %>
    <% end %>
  </fieldset>
  <%= submit_tag %>
<% end %>