Now available in the UK, Jajah simplifies making calls using VoIP technology.
Unlike many other services, you don't have to install extra equipment to make a phone call — you make it over your normal telephone.
To use Jajah, you visit the website to enter your phone number and the number of the person you want to call, and click "Call".
Both your telephone and the person you're trying to reach will ring, so you simply pick up your handset and connect.
Rates for calls are quite low, with a call from London to New York cost 1.2pence a minute, and a call to Bangkok just 2.2pence per minute.
It can even be used for mobile-to-mobile calls that cost 18pence a minute.
Additional services include a "call schedule" function, so that you can set-up calls in advance.
Jajah has been available in the US since March.