If you own some “unused” web domains that still get some traffic because that domain is listed in an online web directory or printed on your old business card, here’s an opportunity to monetize those visitors without having to show them messages like “Domain under construction” or 404 errors.

Google has just extended the “AdSense for Domains” program to International AdSense publishers and the program now supports non-English languages as well.

The program initially launched in December but was available only to publishers located in North America with English-language accounts.

To get started, login to your Google AdSense account and click the “AdSense for Domains” link under the AdSense Reports tab. Here are detailed instructions on how to set up your vacant domain for AdSense ads. It requires you create a new CNAME record which have a value pub-123.afd.ghs.google.com. where pub-123 is your AdSense publisher ID.

The AdSense for Domains program will also appeal to users who have purchased web domains only for the purpose of Google Apps and have no plans of creating / hosting a public website. In that case you may have Gmail, Google Calendar, etc. in sub-domains (mail.xxx.com or calendar.xxx.com) while you may use the main domain (www.xxx.com) for AdSense ads.