External script to check which payment method is Active in Magento.
Below is the code to display all payment method.

create new file in root of the magento source and add below code in that file

require_once('app/Mage.php');
umask(0);
Mage::app();
$payments = Mage::getSingleton('payment/config')->getActiveMethods();
$payMethods = array();
foreach ($payments as $paymentCode=>$paymentModel)
{
$paymentTitle = Mage::getStoreConfig('payment/'.$paymentCode.'/title');
$payMethods[$paymentCode] = $paymentTitle;
}
echo "<pre>";
print_r($payMethods);