This is the code I got the other day from someone here. In Control Panel, click on General, then click the HTML Includes tab.

In the header box, paste this... I put notes in here for you to swap out with your logo info.

<table width="100%" class="t_inner" cellpadding="0" cellspacing="0">


<html>
<head>
</head>
<body>
<tr>
<td colspan="3" class="lefttdheader">
<span style="float:right">Community Forum</span>
<span style="float:left">The Forum Name</span>
</td>
</tr>

<tr>
<td class="alt-2" align="left">
<img src="yourlogo.jpg" alt="Your Forum Logo Name" border="0" />
</td>
</tr>
</table>
</body>
</html>