class Example_OrderMod_Model_Observer{

  public function doSomething($observer){
    $order = $observer->getEvent()->getOrder();

    $id_ordine = $order->getRealOrderId();
    $cliente = $observer->getEvent()->getOrder()->getCustomerName();

    foreach ($order->getAllItems() as $item) {
    //$item is an instance of Mage_Sales_Model_Order_Item

      $quantita =  $item->getQtyOrdered();
      $codice_giglio =  $item->getSku();

      //echo $item->getData('size');
      var_dump($item->getAttributeText('size'));
      var_dump($item->getProductOptionByCode('size'));
      var_dump($item->getProductOptionByCode('famiglia'));

    }
//    die();
  }
}

$product = Mage::getModel('catalog/product')->load($item->getProductId());
$size = $product->getAttributeText('size');

$product = $item->getProduct();

function getAttr($product_id, $attributeName) {
    $product = Mage::getModel('catalog/product')->load($product_id);
    $attributes = $product->getAttributes();
    $attributeValue = null;
    if(array_key_exists($attributeName , $attributes)) {
        $attributesobj = $attributes["{$attributeName}"];
        $attributeValue = $attributesobj->getFrontend()->getValue($product);
    }
    return $attributeValue;
}