[jugo]

Use this for your navbar template edit:

<script type="text/javascript">
<!--

function OpenvBChat(){
vBChat = window.open('vBChat.php?$session[sessionurl]','vBChat','directories=no,height='+window.screen.height/2+',width='+window.screen.width/2+',location=no,menubar=no,scrollbars=yes,status=no,toolbar=no')

return false;
}

-->
</script>
<td class="vbmenu_control"><a href="vBChat.php?$session[sessionurl]" onclick="return OpenvBChat();">vBChat</a></td>

It'll open a window only a quater of the size of the user's screen.