[Chris Gwynne]

Edit the header and footer template and you'd basically have two columns, if you're good with HTML. In one column you'd have the add, in the other the forum's HTML structure.

HEADER

<div align="center">
<center>
<table border="0" cellpadding="4" cellspacing="0" width="100%" height="100%">
<tr>
<td valign="top">AD CODE</td>
<td valign="top" width="100%">

You'd put that before the second table started in your Header Template.

FOOTER

</td>
</tr>
</table>
</center>
</div>

You'd put that just after the table finished in your footer template.

Obviously modify the variables such as the width, the alignments and so on to get the look right. Hope this helps.