Endgadget posts a video demo of an iPhone successfully making a phone call over IP. The demo was provided by a company called Truphone who announced today. From the press release:

1. Many people have called for true VoIP calling on Apple's iPhone. Truphone will today prove that it is possible using the iPhone's in-built Wi-Fi capability.
2. Truphone's demonstration will comprise two iPhones connected to Wi-Fi on the DEMOfall 07 stage. A VoIP call will be initiated from one handset, routed via Wi-Fi and the Internet to Truphone's servers, and then back again to the access point and onwards to the destination handset -- a 100% IP phone call.
3. Today's event will be a live demonstration only and is not a commercial launch of Truphone on the iPhone.
4. Truphone does not need to unlock the SIM in order to operate its service for the iPhone.

Voice over IP (VOIP) allows users to use the internet to transmit their voice calles, bypassing AT&T's cellular network (and billing).

Related Forum: iPhone