<?if($UNREAD_PM$>0)?>  
<div id="mymess"><img src="/images/message2.png" onclick="$('#mymess').slideToggle('fast'); $('#mymess2').slideToggle('fast');" title="У Вас нов<?if($UNREAD_PM$>1)?>ы<?else?>о<?endif?>е сообщени<?if($UNREAD_PM$>1)?>я<?else?>е<?endif?>!" border="0"></div>  
<div id="mymess2">  
<div id="close" onclick="document.getElementById('mymess2').style.display='none';return false">X</div><a href='$PM_URL$'>  
<script type="text/javascript" >  
var num=$UNREAD_PM$;  
function comend(comnum){  
var i;  
var str=' сообщен';  
var str2=' нов';  
comends = new Array(  
['ий'],['ие'],['ия'],['ия'],['ия'],['ей'],['ей'],['ей'],['ей'],['ей'],['ей'],['ей'],['ей']  
,['ей'],['ей'],['ей'],['ей'],['ей'],['ей'],['ей'],['ей']);  
comends2 = new Array(  
['ых'],['ое'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых']  
,['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых'],['ых']);  
i = comnum.toString();  
while (i>20)  
{i= i.substring(i.length - (i.length < 3 ? 1 : 2));}  
document.write(comnum,str2,comends2[i],str,comends[i]);  
}  
comend(num);  
</script>  
</a></div><?endif?>  
Выделить код в новом окне  

А это CSS, добавьте его к себе в таблицу стилей:  
#mymess {padding:5px 6px;bottom:0;left:0;position:fixed;z-index:999999;}  
#mymess img {cursor:pointer;}  
#mymess2 {display:none;font-size:24pt;background:#000000;width:auto;height:auto;bottom:0;left:0; position:fixed;z-index:999999; border-top:1px solid #808080;border-right:1px solid #808080;}  
#mymess2 a {font-size:1em;color:#dedede;text-decoration:none;padding:5px 6px;}  
#mymess2 #close {font-weight:bold;cursor:pointer;color:#c0c0c0;float:right;border-left:1px solid #808080;padding:5px 6px;}  
#mymess2 #close:hover {color:#fff}