To link to a products root category based on the location variable you can...
Open product.php
FIND:
Code:
$smarty->assign("product",$product_info);
BEFORE ADD:
Code:
// WCM - Assign Root Category
$product_info['root_category'] = $location[1][0];
$product_info['root_category_link'] = $location[1][1];
// / WCM - Assign Root Category
In skin1/customer/main/product.tpl use:
Code:
{if $product.root_category_link}
<strong>Root Category:</strong> <a href="{$product.root_category_link}" title="{$product.root_category}">{$product.root_category}</a>
{/if}