At the Apple iPhone SDK event, Steve Jobs stated that if someone develops a VoIP program for the iPhone, Apple will allow it if it goes over WiFi and not the cellular network. Apple will in fact BLOCK VoIP applications from running over the cellular data network. 
What in the bloody hell kind of half-ass crippling of VoIP is that? Apparently, Steve Jobs aims to protect their cell network buddy AT&T from having VoIP calls be "minute stealers" from the regular cell network. Of course, AT&T and Apple have some sort of revenue sharing deal from what I understand, so Mr. Jobs doesn't want Apple's purse strings affected by VoIP bypassing the usage of cell minutes either.Seriously though, who the heck goes over their bucket of monthly minutes anyway? Only then does AT&T (& Apple) make extra money after you've used up your monthly cell minutes. If your consistently going over your bucket of minutes you should change your plan. And if you aren't going over your bucket of minutes, then making VoIP calls over your cellular unlimited data plan shouldn't affect AT&T or Apple in the least. Sure, you'll be using some bandwidth, but VoIP uses a heck of lot less data bandwidth than some Internet applications. Heck, get a 6mb email attachment and that's probably equivalent to a couple minutes phone call right there.
VoIP exists on every other smartphone, including Nokia and Windows Mobile. With Steve Jobs handicapping VoIP to just over WiFi, VoIP on the iphone is pretty useless - it cant be used on EDGE. Even Truphone, which one of the first to "hack" the iPhone to allow VoIP on the iPhone only works over WiFi. I'm guessing Apple has protected the cellular data stack from running VoIP applications. Brilliant! Not!
