get payment method in cart magento

for handling payment method display in cart we use event handling  we use config.xml in module or in custom module

app/code/local/regitration/field/etc/config.xml

<?xml version="1.0"?>
<config>
<frontend>
<events>
    <payment_method_is_active>
        <observers>
            <Regitration_Field_Model_observer>
                <class>Regitration_Field_Model_observer</class>
                <method>payment_method_is_active</method>
            </Regitration_Field_Model_observer>
        </observers>
    </payment_method_is_active>
</events>
  </frontend>
</config>



define action in observer file


app/code/local/regitration/field/model/observer.php

<?php
class Regitration_Field_Model_observer {

public function payment_method_is_active($observer){
     $event           = $observer->getEvent();
    $method          = $event->getMethodInstance();
    $result          = $event->getResult();
    $session = Mage::getSingleton('checkout/session')->getQuote();
$shippiingcarriers =  $session->getShippingAddress()->getShippingMethod();
            if ($shippiingcarriers == 'flatrate_flatrate' ){
                    if($method->getCode() == 'cashondelivery' OR $method->getCode() == 'checkmo' OR $method->getCode() == 'paypal_standard' or $method->getCode()=='purchaseorder'){
                        $result->isAvailable = false;
                    }else{
                        $result->isAvailable = true;
                }
            }

}
}
 ?>