<script>
var str = "Ааааааааааааааааааааааааааааааааааа";
var message = str.replace(/(\S{15}[^$])/g,'$1\n');
/*
В итоге получим
Ааааааааааааааа
ааааааааааааааа
ааааа
  */
</script>

<center><div align="left"><table cellspacing="0" cellpadding="0">
   <tr>
   <td width="11" height="22" background="/Design/News/Comments/tcoml.gif"> </td>
   <td align="left" background="/Design/News/Comments/tcomf.gif" style="text-align:left;padding-top:1px"><span class="comtitle"><font color="#663300">
   <?if($EMAIL$)?><a href="$EMAIL_JS$" title="E-Mail"><img border="0" align="absmiddle" src="/Design/News/Comments/E-Mail.png"></a><?endif?>
   <?if($SITE$)?><a rel="nofollow" href="$SITE$" target="_blank" title="Сайт"><img border="0" align="absmiddle" src="http://s15.ucoz.net/t/271/h.gif"></a><?endif?>
   <?if($ENTRY_URL$)?>[<a href="$ENTRY_URL$" target="_blank" title="Перейти на страницу материала">Материал</a>]<?endif?>

   <span style="width:18px;">№<b>$NUMBER$</b></span></font> | Написал(а): <?if($USERNAME$)?><a href="$PROFILE_URL$"><b>$USERNAME$</b></a><?else?><b>$NAME$</b><?endif?> | <span title="$TIME$">$DATE$</span> $MODER_PANEL$</span></td>
   <td width="11" height="22" background="/Design/News/Comments/tcomr.gif"></td>
   </tr>

   </table></div>
   <div align="center">
   <table width="88%" border="0" cellspacing="0" cellpadding="0">
   <tr>
   <td width="120" height="40" background="/Design/News/Comments/com_lv.jpg"></td>
   <td height="40" background="/Design/News/Comments/com_fv.jpg" align="left"></td>
   <td width="21" height="40" background="/Design/News/Comments/com_rv.jpg"></td>
   </tr>
   <tr>

   <td style="PADDING-LEFT: 0px" width="120" align="left" valign="top" background="/Design/News/Comments/com_lf.jpg" class="comleft">
   <?if($USER_AVATAR_URL$)?><img src="$USER_AVATAR_URL$" title="$USER_FULL_NAME$" border="0" width="105" height="103"><?else?><img src="/Avatars/NoAvatar.png" border="0" width="105" height="103"><?endif?></td>
   <td align="left" valign="top" bgcolor="#E1E7D2" class="comright"><div>
   </div>
   <span class="comreg">$MESSAGE$</span><BR><?if($ANSWER$)?><DIV class="cAnswer" style=" CLEAR: both; TEXT-ALIGN: left"><B>Ответ</B>: <span class="comreg">$ANSWER$</span></DIV><?endif?></SPAN></td>
   <td width="21" background="/Design/News/Comments/com_rf.jpg"></td>
   </tr>

   <tr>
   <td width="120" height="21" background="/Design/News/Comments/com_ln.jpg"> </td>
   <td height="21" background="/Design/News/Comments/com_nf.jpg" class="comdown"> </td>
   <td width="21" height="21" background="/Design/News/Comments/com_rn.jpg"> </td>
   </tr>
   </table></div>
   </center><br>

<script type="text/javascript">
var q=document.getElementsByTagName('span'),w=q.length;
while(w--) {
  if (q[w].className=='comreg') {
   q[w].innerHTML=q[w].innerHTML.replace(/(\S{15}[^$])/g,'$1\n');
  }
}
</script>