British mobile operator O2 is conducting a trial of free voice and text services via wi-fi networks.
The O2 Connect will be available to just 1,000 owners of iPhones and Android smartphones initially but if the trial is successful then it will be launched as a commercial service next year.
"This trial will allow us to explore the potential of delivering VoIP services to customers," said O2 consumer mobile chief Richard Porter.
Rather like other VoIP services such as Skype, O2's service will route calls and texts via internet connectivity rather than the cellular phone network, potentially resulting in cost savings to customers.
The promise of cheaper calls often lures smartphone owners to install VoIP applications which offer free access to messaging and cheap calls to normal telephone numbers.
Services such as O2 Connect look set to offer customers a similar solution from their own provider which should negate the need to set up separate accounts. It seems likely O2 would look to bundle apps and phone settings on O2-sold contract phones to enable such a service when it arrives.