to me it's sounds like skype, yahoo mess...... what is the difference?
for yahoo and skype we need account , and for this , we only need this app to be in both devices .
we can make a call using this app like we do using are network.
well,obviously it is quite different than that of jabber/real voip cuz they require username etc and also they dont sync with phone contacts,do they ? it more sounds like a phone to phone free call requiring only an app,nothing more or less so if it could be ported ever then we shouldnt just seek any reason .ciao