How to hide a menu once a user logged in - Joomla

$user =& JFactory::getUser();

$user_id = $user->get('id');

This returns the user id of the user. Therefore the code to do this is check whether the current user has a valid id (i.e. they are logged), if not load the module:

<?php
$user =& JFactory::getUser();
$user_id = $user->get('id');
if (!$user_id)
{
?>
<jdoc:include type="modules" name="left" />
<?php
}
?>

i mentioned as JOOMLA at the end of the title, i guess...

oh.. sorry... & thank you 4 ur suggestion