Aianna

Free calls with excellent quality from your smart phone over WiFi, 3G and GPRS.

Very strange service with many technical issues. You can try at your own risk.

But be careful, it can drain your phone battery and your money very fast.

May be it is better to use Sipmobile?

Below the description.

Aiannaone Telecommunications is an affordable and easy-to-use broadband telephone and videophone service. Designed with both residential and business customers in mind, AiannaOne allows anyone with broadband (high-speed) Internet access to use their regular phone to make calls to anywhere around the world. AiannaOne subscribers with videophones can make video calls from anywhere Ethernet is offered that is DSL or Cable. All AiannaOne subscribers get worldwide UNLIMITED calling to other AiannaOne subscribers at no extra charge. Calls to non-AiannaOne international numbers (outside the U.S. and Canada) are charged at a very low per minute rate. No contract.

Please note: to make calls you need sign-up to Aiannaone account.

Main features:

Connectivity through WIFI, 3G, EDGE and GPRS

Making and receiving VoIP audio and video calls

Get a second Land Line number for your Mobile

Contacts (phone book)

Loudspeaker

Time, call status logs

Last calls log

Redial

sending and receiving SMS over VoIP