Very nice hack mholtum, but there is one slight problem in using the "<marquee>" scrolling javscript tag. If you view the scrollbar using Firefox and then minimize your page smaller. You will notice that the scrollbar box and scrolling text does not minimize to fit the page like it does in IE. Instead it will stay full width and go off the page unlike the other forum frames which re-size to fit.
I found this problem out ages ago, it a problem with Firefox not supporting the <marquee> code tag correctly, it's an IE thing only which fully supports it.
So I did this with you code in removing the marguee and making the text red to highlight it better. Now it will work proper in IE and Firefox and all other browsers, all be it without scrolling text if anybody wants the none scolling version showing RED text (can be changed to suit).
Code:
<if condition="$bbuserinfo[usergroupid] == 2 AND $bbuserinfo['posts'] <= 0">
<table cellpadding="$stylevar[outerborderwidth]" cellspacing="0" border="0" class="tborder" width="$stylevar[tablewidth]" align="center"><tr><td>
<table cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%">
<tr>
<td class="panelsurround" align="center">
<div class="panel"><div align="$stylevar[center]">
<fieldset class="fieldset" style="margin:0px 0px 0px 0px">
<legend>Announcement</legend>
<strong><font color="red"><phrase 1="$bbuserinfo[username]">$vbphrase[welcome_x]</phrase> Our logs show you've never posted - please make a post or your account may be removed as inactive.</font></strong>
</fieldset>
</div></div>
</td>
</tr>
</table>
</td></tr></table><br /><br />
</if>
<if condition="$bbuserinfo[usergroupid] == 1">
<table cellpadding="$stylevar[outerborderwidth]" cellspacing="0" border="0" class="tborder" width="$stylevar[tablewidth]" align="center"><tr><td>
<table cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%">
<tr>
<td class="panelsurround" align="center">
<div class="panel"><div align="$stylevar[center]">
<fieldset class="fieldset" style="margin:0px 0px 0px 0px">
<legend>Announcement</legend>
<strong><font color="red">Please register to participate in the Forum discussion taking place - it's fast, easy and free!</font></strong>
</fieldset>
</div></div>
</td>
</tr>
</table>
</td></tr></table><br />
</if>
None the less, still a very cool hack and very useful indeed.