Google AdSense Revenue Sharing

how can i create additional field to my forum database which contain user's google_ad_client.
and how can i use it in the viewtopic_body template?

Code:


<script type="text/javascript"><!--
google_ad_client = "???????????????????????????";
/* jewelry 300x250 */
google_ad_slot = "3187488398";
google_ad_width = 300;
google_ad_height = 250;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>