VoIP is great isn't it? All those free calls around the world to your mates and family without the hefty bills to match? Shame you can't get it on your mobile then isn't it.

Well, now it appears you can. Although still in beta fring is a 3G mobile application that allows you to make free mobile calls and send instant messages (chat) to other fring users and PC based VoIP services such as Skype and Google Talk at no extra costs other than data charges.

The benefit and key selling point is that because the fring application only uses the data connection you aren't charged the cost of the actual call.

According to the makers of the mobile phone application fring works transparently over 3G networks while bypassing traditional mobile voice and SMS text messaging services. This means that fring enables mobile-to-mobile calls, mobile-to-landline calls, and mobile-to-PC calls including integration into Skype and Google Talk services wherever you are.

fring, which launches later this year, requires a 3G handset to work and currently works on Nokia's 6630, 6680, 6681, 6682, N70, N90 models - i.e., the Symbian operating system (we tried it on the N70).

In practice the phone application does exactly what it says it does and as long as you've got a decent connection you will be able to make phone calls on the cheap. In our tests around the UK we found that while you didn't need 3G coverage for it to work the performance was very much "you speak, they speak" rather than a full following conversation.

That said, once we got into a 3G area holding conversations via Skype and GoogleTalk was the same as if we had made the a voice call via in the standard way.