I've talked about the Truphone VoIP solution here on this blog a couple of times in the past and have had it on my iPhone for several months. Now that my ZDNet Smartphones & Cell Phones blog focuses on phones you may be asking why I am posting about a phone solution here on the Mobile Gadgeteer. A new Truphone (iTunes link) client was just released for the Apple iPod touch that turns it into a VoIP phone, but it is not a cellphone. Highly respected VoIP blogger and friend Andy Abramson has an excellent blog post on why TruPhone on the iPod touch is a game changer in the VoIP space.
Fring has been available on the iPhone App Store for a while now too, but from everything I have read Truphone offers a higher quality phone call experience. Truphone also lets you call Truphone members and Google Talk members for free while Fring focues on Skype and Fring members.
Truphone for the iPod touch has it's own user interface, compared to Truphone for the iPhone, and lets you call other Truphone or Google Talk members for free. You cannot make calls to landlines and mobile phones yet, like you can with Truphone on the iPhone or S60 devices.
You will need a second generation iPod touch and a headset with a microphone to use Truphone, but with the large number of iPod touch and iPhone users there could be a real community of people available that you can now call for free when connected to a WiFi access point. Plus, as Andrew pointed out there are some amazing features coming soon.