If you are using Google Adsense as publisher, you should know by now that you can also use Google for Domains for your undevelop domain names. Read here if you missed this article (Extending Adsense for domains to all publishers). All North American based publishers should have their Google for Domains access starting December 18, 2008.
You need to setup your domain name www A record to the CNAME (alias) with your unique adsense ID provided to you. Here's the step-by-step setup to use Google for Domains.
To have your own reseller account, please read http://reseller.king.net article.