The complete list of top-level domains (TLDs) in which we can provide domain registration services (including new registrations, renewals, and transfers) can be found on this page.
Currently we offer only generic top-level domains (gTLDs) and the .us ccTLD. If you want to register a domain in another country's top-level domain (ccTLD), you will need to contact a registrar accredited by that country. (Note: Although some countries have chosen to market them otherwise, all two-letter TLDs are ccTLDs.)
If you already have such a domain and wish to use it with our service, this is generally no problem. Just add your domain to our control panel as an existing domain, create DNS for it, and have your registrar update your name server information accordingly.
See also this entry about adding new TLDs.