Create an observer for sales_order_place_after
<events>
<sales_order_place_after>
<observers>
<orderenteredby>
<type>singleton</type>
<class>orderenteredby/observer</class>
<method>implementOrderMethod</method>
</orderenteredby>
</observers>
</sales_order_place_after>
In Observer.php
class MagePal_OrderEnteredBy_Model_Observer
{
public function implementOrderMethod($event)
{
$_order = $event->getOrder();
if($this->_isAdmin()){
$_user = Mage::getSingleton('admin/session');
$firstname = $_user->getUser()->getFirstname();
$lastname = $_user->getUser()->getLastname();
$enterBy = "Order entered by {$firstname} {$lastname}";
}
else{
$enterBy = 'Ordered Online';
}
$_order->addStatusHistoryComment($enterBy)
->setIsVisibleOnFront(false)
->setIsCustomerNotified(false);
return $this;
}
protected function _isAdmin(){
if(Mage::app()->getStore()->isAdmin()){
return true;
}
if(Mage::getDesign()->getArea() == 'adminhtml'){
return true;
}
return false;
}
}
For more info on how to create an observer see Change Magento default status for duplicated products