[drc0]

Piggybacking the question to state a general info:

There are voip operators like the italian mtalk that give you free local national numbers, free calls between users of the same provider, but the call is not encrypted.

This have the good thing that anyone can choose the preferred provider, you can receive calls also from "traditional" phones.

A phone number is like a mailbox, it's clearly provider independent, but sadly it's often non free calling between different operators.