$skuList = array('SKU-1', 'SKU-2',...,'SKU-n);
$_productCollection = Mage::getModel('catalog/product')
->getCollection()
->addAttributeToFilter('sku', array('in' => $skuList));
OR
$_productCollection = Mage::getResourceModel('catalog/product_collection')
->addAttributeToFilter('sku', array('in' => $skuList));