UK-based ROK Mobile Communications has developed a VoIP application that uses your mobile telephone like a Bluetooth headset to connect to the company's network.

Once downloaded onto a Windows computer, the ROK Viper client also installs onto a compatible phone handset and, when run, copies the contact list from the phone to display it on the PC screen. It also displays presence information, indicating if that contact is currently logged onto the ROK network. Clicking on the name dials the contact, with the call being routed over Bluetooth to the handset.

All calls are free, but right now can only be made to other ROK users. The next few weeks will see the ability to dial any number, at a price, added. Such calls will be routed over the internet where possible, so charged at a very low rate, in a similar fashion to the popular SkypeOut service.

Currently, only a few handsets are supported (Nokia 6630, 6680, 6681, 6682, N70 and N90), but ROK expect to have over 100 handsets supported by the end of the year.

The alternative would be to use Skype with a Bluetooth headset connected to your PC. Obviously, this wouldn't integrate your phone address book, and can be difficult to configure, but it would mean you could phone a lot more people for free. ®