mahemto cart use on set description

 ===Set Description===================================
 app/code/core/Mage/Sales/Model/Quote.php
 public function addProductAdvanced(
 after this coding :-
 $items[] = $item;
 $item->setDescription($_customValue);

 =========================================
 app/design/frontend/rwd/nassaunationalcable/template/checkout/cart/item/default.phtml
 $_item->getDescription();