<input type="button" accesskey="y" value="!!!" onclick="simpletag('!!!','','','message',''); return false;" class="codeButtons" title="Важно" name="!!!" />  
<input type="button" accesskey="y" value="ps" onclick="simpletag('ps','','','message',''); return false;" class="codeButtons" title="P.S" name="ps" />  

сохраняемся!!!  
идем Общий вид страниц форума и после $BODY$ пишем следующее  
Code
<script type="text/javascript" language="javascript">   
e=document.getElementsByTagName("TD");   
for(k=15; k<e.length;k++) {   
if(e[k].className=='posttdMessage') {   
s=e[k].innerHTML;   
while (s.indexOf('[!!!]') != -1){   
s=s.replace('[!!!]','<fieldset><legend><font style="font-size: 10px; font-family: Verdana; color: red;">Важно!!!</font></legend><font style="font-size: 11px; font-family: Verdana; color: red;">'); s=s.replace('[/!!!]','</font></fieldset>');   
e[k].innerHTML=s;   
}   
} }   
</script>  
<script type="text/javascript" language="javascript">   
e=document.getElementsByTagName("TD");   
for(k=15; k<e.length;k++) {   
if(e[k].className=='posttdMessage') {   
s=e[k].innerHTML;   
while (s.indexOf('[ps]') != -1){   
s=s.replace('[ps]','<fieldset><legend><font style="font-size: 10px; font-family: Verdana; color: purple;">P.S</font></legend><font style="font-size: 11px; font-family: Verdana; color: purple;">'); s=s.replace('[/ps]','</font></fieldset>');   
e[k].innerHTML=s;   
}   
} }   
</script>