I was checking out TUAW this morning and saw that a very cool VoIP application is under development for the Apple iPhone. This is not an application for jailbroken phones, but for iPhones that have been upgraded to the latest firmware supporting 3rd party applications. What makes this VoIP application particularly powerful is the ability to transfer a cellular call to WiFi during the call as shown in the YouTube video below. iCall seems to work quite well and will definitely be one of the first applications I plan to look for when the iPhone application store is launched.
iCall is available now as a Windows PC based VoIP client and currently all calls you make or receive are free within the U.S. or Canada. They also have an iCall Pro version that has a monthly fee associated with it that supports more features on your PC.
I think VoIP on the iPhone has some great possibilities since the iPhone does such a great job at handling switches between cellular towers and a WiFi connection. Is anyone else excited about VoIP on the Apple iPhone?