Magento : Get configurable product SKU and it's associated product SKU in Cart

Write This in "templet/checkout/cart/item/default.phtml"
<?php

$_item = $this->getItem();

echo $temp = $_item->getProductId();
echo "<br/>";
$_product = Mage::getModel('catalog/product')->load($temp);
echo "Config. Product :";
echo $_product->getSku();
echo "<br/>";

echo "Simple Product :";
echo $_item->getSku();