While most everyone and their mothers likely has a cell phone and an accompanying service for it, it still would be pretty cool to take what is otherwise a PMP in the iPod Touch and use it to make phone calls. It isn’t that hard to do either.
You actually have two options if you want to utilize the Touch to make low-cost, budget-worthy calls.
1. Hack It
You can actually poke around your gadget yourself and tweak it to allow phone calls over wi-fi. All you’ll need is a jailbroken iPod Touch, a VoIP app and a pair headphones with mic. Make sure the mic works specifically for the Touch – iPhone’s headphones don’t.
Basically, you’ll need to install the app (Fring seems to be the most popular, ATM), set up an SIP or VOIP account (Skype, Freecall, any other service that is compatible with your app) for outbound calls and set up an inbound number via another web service (CallCentric, IPKall) so you can receive calls.
There is a more comprehensive (albeit older) guide on Lifehacker about how to do this.
2. Use TruPhone
TruPhone is a relatively new iPod Touch app available for free download on iTunes that allows users to make and receive calls over VoIP. It’s still pretty limited, though, with no support for Skype and MSN VoIP users, although the developers have announed those two services are in order. Also on the near horizon are outgoing calls to landlines. For the price of free, however, and a relatively easy setup, it’s a pretty easy sell.