From PhpCOIN Documentation
The Domains module is a series of tables that allow a web-host to track domain name registration and expiry information, along with the server that the domain is hosted on (if the web-host has more than one server), and a click able link to the "Control Panel", if any, for the domain.
Domain records can be created manually by an admin, or automatically when a surfer places an order for a product and the product has a domain name component.
phpCOIN has a built-in WHOIS module to allow customers to search for available domains, as well as a link to click for available domains that can take them back to the order form or to an external registration site, whatever the web-host needs.
The "Summary" page automatically lists any domains dues to expire within 60 days, giving you plenty of time to renew.
The admin parameter to disable domains (and the associated WHOIS lookups) will remove all menu links and buttons that reference domains and/or WHOIS, and if a surfer tries to access domains or WHOIS data directly via URL parameters they will receive a "disabled" notice.
Add/Remove Domain TLD's
To add or remove Domain TLD's, just go to: Admin -> WHOIS Lookups and set up whatever extensions you need. Don't forget to set them to active, otherwise they will not show in the extension list.