
$orderCollection = Mage::getModel('sales/order')->getCollection()
->addAttributeToSelect('increment_id')
->addAttributeToSelect('customer_firstname')
->addAttributeToSelect('customer_lastname')
->addAttributeToSelect('customer_email')
->addAttributeToSelect('coupon_code')
->addAttributeToFilter('coupon_code', 'YOUR_COUPON_CODE_HERE');
print_r($orderCollection->getData());