ALTHOUGH I DON'T HAVE much time for voice calls made over data connections, I'm using both Skype and Viber on my iPod Touch because the handset doesn't have a 3G antenna. It's handy being able to make and take calls on the Touch while in wifi coverage and to walk the streets, travel on Irish Rail and climb mountains with those free calling options. The iPod Touch does not come with an over-the-air data service but my Mifi dongle connects to the Touch and shares its 3G signal that way. According to stats I've reviewed with O2.ie, I'm using around one megabyte for every five minute phone call. If I was roaming, those five minute calls would cost me one euro over Viber or around five euro if I was using my regular handset to handle the voice calls. Some international users pay more. I'm not trying to get more than a handful of contacts onto my iPod Touch handset so if you feel left out because I don't reciprocate with a Skype or Viber contact exchange, just know I'm not trying to turn the Touch into a phone and text me on my normal number.
Listening to Viber cross-talk on the O2 Forum.