/administrator/modules/mod_status/mod_status.php

<?php
/**
 * @version		$Id$
 * @package		Joomla.Administrator
 * @subpackage	mod_status
 * @copyright	Copyright (C) 2005 - 2010 Open Source Matters, Inc. All rights reserved.
 * @license		GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access.
defined('_JEXEC') or die;

// Initialise variables.
$config = &JFactory::getConfig();
$user = &JFactory::getUser();
$db = &JFactory::getDbo();
$lang = &JFactory::getLanguage();

// Get the number of unread messages in your inbox.
$query = new JQuery;

$query->select('COUNT(*)');
$query->from('#__messages');
$query->where('state = 0 AND user_id_to = '.(int) $user->get('id'));

$db->setQuery($query);
$unread = (int) $db->loadResult();

// Set the inbox link.
if (JRequest::getInt('hidemainmenu')) {
	$inboxLink = '';
} else {
	$inboxLink = JRoute::_('index.php?option=com_messages');
}

// Set the inbox class.
if ($unread) {
	$inboxClass = 'unread-messages';
} else {
	$inboxClass = 'no-unread-messages';
}

// Get the number of logged in users.
$query = new JQuery;

$query->select('COUNT(session_id)');
$query->from('#__session');
$query->where('guest <> 1');

$db->setQuery($query);
$online_num = (int) $db->loadResult();

// Set the logout link.
$task = JRequest::getCmd('task');
if ($task == 'edit' || $task == 'editA' || JRequest::getInt('hidemainmenu')) {
	 $logoutLink = '';
} else {
	$logoutLink = JRoute::_('index.php?option=com_login&task=logout');
}

require JModuleHelper::getLayoutPath('mod_status', $params->get('layout', 'default'));