Claudio
Not exactly what you are asking for, but for extremely low rates to Europe/Asia/Australasia that you can access from any normal phone, try
http://www.nobelcom.com . With 4c/min from US to Australasia, we gave up on messing with internet telephony.
Regards
JR
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1