For those wanting to add a Google Adsense block, copy the following (with your advertiser id) into a custom block:
/* PHP CODE HERE */
/* BODY HERE */
$body = <<<EOF
<center>
<script type="text/javascript"><!--
google_ad_client = "pub-5168900358893374";
google_alternate_color = "000000";
google_alternate_ad_url = "http://banners.undergroundnews.com/CS.gif";
google_ad_width = 728;
google_ad_height = 90;
google_ad_format = "728x90_as";
google_ad_channel ="3810782578";
google_ad_type = "text_image";
google_color_border = "000000";
google_color_bg = "081750";
google_color_link = "FFFFFF";
google_color_url = "CCCCCC";
google_color_text = "FFFFFF";
//--></script>
<script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</center>
EOF;
You can add this to your forum through the control panel (Control Panel -> Custom Islands -> Custom Island #1); to add the custom island to your forum you will need to edit the forum(s) that you wish it to be provided on and select the island from the "Custom Island Insert" dropdown on the "Custom Inserts" tab.