To turn the ipod into a US Cell Phone when tethered to data/wifi, you need 3 apps:
Simplest setup: Google Voice Account + Talkatone (www.talkatone.com/)
-GV Connect App. Free voice mail, texting, permanent number.
-Whistle Account – Free calls up to 20 minutes. Receive and make calls, no voice mail, yes permanent number.
If you can’t register for a google voice account because you are already outside the US, use a free VPN service like proxpn.com to make your computer appear to be in the USA.
The annoying thing about GV Connect is that you have to log in everytime. You may be able to reduce the number of relogins by using a backgrounding app to keep this and Whistle on.
When you dial from GV Connect, you will have it ring Whistle. Then you answer Whistle and it connects your call. Google requires an intermediary to make the calls.. you cannot call directly from google on a mobile device, or else apple would get mad. Though you can from skype.