Here is my very Cool domain with co.cc, you can show and see it :
First, if you’ve previously changed your domain’s nameserver, make sure you change it back to point to your registrar’s default nameservers.(If you’re not sure, you probably have not changed this and don’t need to change anything.) Second, create the following CNAME (alias) records for your www host using your domain registrar. You can find your unique identifier on the AdSense for domains setup page:
Host Name/Alias: Record Type
Value/Destination : www CNAME (alias)
pub-xxxxxxxxx.afd.ghs.google.com. (where pub-xxxxxxxxx is your unique ID listed on the AdSense setup page)
Next, create the following A records for your domains at your domain registrar (view instructions for common domain registrars): Host Name/Alias Record Type with Value/Destination
@ A (address) 216.239.32.21
@ A (address) 216.239.34.21
@ A (address) 216.239.36.21
@ A (address) 216.239.38.21
Note: Please be sure that these four A records are the only existing A records for your domain. Presto! We’ll start serving ads to traffic that comes to your site as soon as the records validate (usually less than 24 hours). For information on common DNS terms including both A and CNAME records, visit the Google Apps Basic Guide to DNS.