New web-based telephony service, Jajah, is offering free telephone calls between registered users across the world.

Sign-up is free and calls may be made to and from landline or mobile telephones. However, they are only free if initiated between landline numbers to certain countries. These include the US, Australia, many European countries, Canada, China and parts of South America.

Daniel Mattes, Jajah's co-founder, is confident that the service won't be abused: 'We believe we can trust our customers to behave in a manner that best serves the larger community, and we are counting on them using a variety of services beyond free calling.'

Jajah relies on a 'fair use' policy to ensure the service isn't overwhelmed. This policy requests that heavy users of free calling also use some of Jajah's paid services. 

These include calling a non-registered user, SMS messaging or calling between certain countries not on the free list. Here, rates are still competitive compared with BT.

Jajah's web based telephony service uses VoIP communication technology in a novel manner. Users enter their telephone number and the number they want to call on jajah.com. There is currently a free five minute call from the UK to a landline anywhere in the world.

Their own telephone then rings and upon answering the telephone of the person they're calling rings. So the call, although routed through Jajah's servers, now operates independently of any PC.

Jajah's other co-founder, Roman Scharf, explained: 'With Jajah, you place a regular call and talk on your phone the way you always have; we simply ask that you dial the call from our website.'

Using Jajah removes the need for VoIP handsets, software and a fast broadband connection to handle the data stream. Users do however need to have internet access to initiate calls.

The internet telephony marketplace has been very active since Ebay's multi-billion dollar acquisition of Skype in October of last year.

Jajah has been operational since February and is financially supported by Sequoia Captial, the venture capitalists that bankrolled Google, Yahoo! and many other Silicon Valley startups.