$order = Mage::getModel('sales/order')->load($orderID);

if ($order->hasInvoices()) {

    $invIncrementIDs = array();

    foreach ($order->getInvoiceCollection() as $inv) {

        $invIncrementIDs[] = $inv->getIncrementId();

    //other invoice details...

    } Mage::log($invIncrementIDs);

}

$order = Mage::getModel('sales/order')->load($orderID);

foreach($order->getShipmentsCollection() as $shipment)

{

    Mage::log($shipment->getData()); //get each shipment data here...

}

$productId = $_item->getProduct()->getId(); //for order emails

//$productId = $_item->getProductId(); //for invoice emails

$product = Mage::getModel('catalog/product')->load($productId);

$attributes = $product->getAttributes();

//Get a list of all PRODUCT ATTRIBUTES you want to show in this array...

$dispAttribs = array('hardrive', 'memory', 'processor'); 

foreach ($attributes as $attribute) {    

        $attributeCode = $attribute->getAttributeCode();

        if(!in_array($attributeCode, $dispAttribs)) continue;

        $label = $attribute->getFrontend()->getLabel($product);

        $value = $attribute->getFrontend()->getValue($product); 

        echo "<br /><strong>" . $label . ":</strong> " . $value;

}