YouFon can also make free voice calls between mobile phone and introduce different.
To explain why.

Please look at the screen.

The two screens in Japan SoftBank (NOKIA E61) in the YouFon Call, docomo (NOKIA E71) is to screen incoming.

(This is NOKIA E61 with SoftBank SIM Card)

(This is NOKIA E71 with docomo SIM Card)

You can also make free voice calls between mobile phones have to deal with different carriers. The same can be carriers of any country in the world.

YouFon the GSM and WCDMA mobile phones and radio will not use. WiFi uses radio only. So you can be able to make free calls.

NOKIA E-series and N-series YouFon immediately if you can try.

http://www.youfon.com/

Depression of the world was coming. Let us YouFon dramatically reduce mobile phone charges.