Tesco has launched a new VoIP service for mobile phones that allows it to use Wi-Fi networks to cut customer's call costs.

Tesco Talk Wi-Fi is the product of a trial with Freshtel launched two months ago, when TechRadar got a hands-on with the new service.

Easy sync

Downloaded as an application to the mobile (currently only on Symbian), the service automatically syncs with the SMS inbox and contact list.

The application, which can be set to run on start-up, will automatically detect whether the other person is on the same service, allowing free calls, or whether it can route the call over Wi-Fi to offer a cheaper service.

The handsets currently able to offer the service are the same as used for the trial: the Nokia N95, N81, E65 and E51, but more are likely to be added in the near future.