Yes indeed it does.

AsteriskC2D routes the call over the GSM network, so you’re free to use AsteriskC2D on your iphone anywhere you get any form of a data signal, WFI, GSM, 3G, or Edge. This is fully supported by Apple and in no way breaches there terms of use.

In fact you configure your AsteriskC2D to route the voice call anywhere, so if you’re in a hotel you can have AsteriskC2D route the calls to your hotel phone for you.  The person on the other end will have no idea that you’re calling from the hotel phone and not your iPhone, or indeed you deskphone at your office.