I inserted the following code into a text widget, but the ad is not showing up:
<script type="text/javascript"><!--
google_ad_client = "ca-pub-0771491387691802";
/* Block theme */
google_ad_slot = "2907786499";
google_ad_width = 250;
google_ad_height = 250;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
you can see a sample page at http://216.119.98.135/shop. the ad should appear in the right sidebar.