app/views/admin/merchandise/products/_shipping_rates_form.html.erb
<% @all_shipping_rates.each do |rate| %>
<div id='rate_<%= rate.id %>' class="property_form left span-9 last">
<% checked_rate = @product.shipping_categories.detect {|c| c.shipping_rate_id == rate.id } %>
<div class='span-8'>
<%= check_box_tag "product[shipping_rate_ids][]", rate.id, checked_rate ? true : false %>
<%= rate.name %>
</div>
</div>
<% end %>