1. You Want cart page to view the SKU number :
You can use below code in your : app/design/frontend/youtheme/yourtheme/template/checkout/cart.phtml
<?php echo $this->__(‘SKU Number’) ?>
And add item section this : app/design/frontend/youtheme/yourtheme/template/checkout/cart/item/default.phtml
<?php echo $_item->getSku() ?>
2. You want to view the Page View :
app/design/frontend/youtheme/yourtheme/template/catalog/product/view.phtml
<!– Write SKU –>
<?php echo $this->__(‘SKU Number :’); ?> <?php
$sku = Mage::getModel(‘catalog/product’)->load($_product->getId())->getSku();
echo $sku; ?>
<!– Sku End –>
its is working for my side.