panels/users_online/languages/en.php

<?php
/* eoCMS is a content management system written in php
    Copyright (C) 2007 - 2009  James Mortemore, Ryan Matthews
    http://www.eocms.com
   This work is licensed under the Creative Commons
   Attribution-Share Alike 3.0 United States License.
   To view a copy of this license, visit
   http://creativecommons.org/licenses/by-sa/3.0/us/
   or send a letter to Creative Commons, 171 Second Street,
   Suite 300, San Francisco, California, 94105, USA.
   Additional license terms at http://eocms.com/license.html
*/
$PANEL_LANG = array();

$PANEL_LANG['uo_title']         = 'Users Online';
$PANEL_LANG['uo_guests_on']     = 'Guests Online: ';
$PANEL_LANG['uo_members_on']    = 'Members Online: ';
$PANEL_LANG['uo_total_on']      = 'Total Members: ';

?>

panels/users_online/index.php

$body .= '<div class="panel-header">'.theme('title', 'Users Online') .'</div>'. theme('start_content_panel');

$body .= '<div class="panel-header">'.theme('title', $PANEL_LANG['uo_title']) .'</div>'. theme('start_content_panel');

$body .= 'Guests Online: '.$guests.'<br />Members Online: '.$members.'<br />Total Members: '.$total_users;

$body .= $PANEL_LANG['uo_guests_on'].$guests.'<br />' .$PANEL_LANG['uo_members_on'].$members.'<br />'.$PANEL_LANG['uo_total_on'].$total_users;