Here is a quick code to get product information with SKU value.
Get product information by sku
// Get product by sku
$sku = "microsoftnatural";
$product = Mage::getModel('catalog/product')
->loadByAttribute('sku', $sku);
// print product data
echo "<pre>"; print_r($product->getData()); echo "</pre>";
Get product id by sku
$productIdBySku = Mage::getModel('catalog/product')
->getIdBySku('microsoftnatural');
echo $productIdBySku;
Hope it helps. Thanks.