As the day for the Apple iPhone 3G approaches, I have one question: who will introduce the first voice over WiFi application for the iPhone? Now I know people have done this before to varying degrees, to me what matters is who gets their app in the store first.

No disrespect to my friends at Jajah and RingFree, of course. They do VoIP, and have an "app" for the iPhone, but it's a web page, not an app that you can get through the app store. The calls go over the GSM network.

Why is this "native" VoIP important? For those of us who live where the GSM network is cheap, it may not be such a big draw. When you're roaming, different story entirely. Making a call over WiFi may be less convenient, but it's likely a hell of a lot cheaper than paying roaming charges with your carrier.

My guess is that Truphone will bring their wonderful Nokia application to the Apple iPhone first before others. That's only a guess. What do you think?