Magento Dispatch Observer

magento_observer_dispatch

<?php 

class Mage_Customer_AccountController extends Mage_Core_Controller_Front_Action
{
....

    /**
     * Dispatch Event
     *
     * @param Mage_Customer_Model_Customer $customer
     */
    protected function _dispatchRegisterSuccess($customer)
    {
        Mage::dispatchEvent('customer_register_success',
            array('account_controller' => $this, 'customer' => $customer)
        );
    }

....

}