In View Source, I see this:
<div id="side-main">
<div class="textwidget"><!-- Begin: AdBrite, Generated: 2008-09-09 13:14:34 --> <script type="text/javascript"> var AdBrite_Title_Color = '0000FF'; var AdBrite_Text_Color = '000000'; var AdBrite_Background_Color = 'FFFFFF'; var AdBrite_Border_Color = 'CCCCCC'; var AdBrite_URL_Color = '008000'; try{var AdBrite_Iframe=window.top!=window.self?2:1;var AdBrite_Referrer=document.referrer==''?document.location:document.referrer;AdBrite_Referrer=encodeURIComponent(AdBrite_Referrer);}catch(e){var AdBrite_Iframe='';var AdBrite_Referrer='';} </script> <script type="text/javascript">document.write('<scr'+'ipt src="https://ads.adbrite.com/mb/text_group.php?sid=836740&zs=3330305f323530&ifr='+AdBrite_Iframe+'&ref='+AdBrite_Referrer+'" type="text/javascript"></scr'+'ipt>');</script>
<div><a target="_top" href="https://www.adbrite.com/mb/commerce/purchase_form.php?opid=836740&afsid=1" style="font-weight:bold;font-family:Arial;font-size:13px;">Your Ad Here</a></div>
<!-- End: AdBrite -->
</div>
The start of which is “Text Widget”. So if you go to Design>Widgets I suspect you have a text widget at the top that has the Adbrite code in it. Delete the widget and you’ll delete the code.