Please, stop the ridiculous N WiFi rumors.
The current iPhone can't even come close to saturating a G conection. In fact, it can't even saturate a good high-speed home Internet connection.
I have 20mbit/sec (burstable to 25 mbit/sec) service from Cox. I've tested it using SpeedTest from both my PC and my MacBook (forcing connection to the G side of my router), and I am able to attain that speed.
With my iPhone connected through WiFi, the best I've been able to get is 5mbit/sec - on a good day. That's just 1/4 of my Internet connection speed. I've tried it on other's routers and had the same result. As well, other people have reported a similar maximum speed here.
N WiFi is absolutely unnecessary for the iphone. It would be a waste of money and a waste of battery power, and Apple is not that stupid.
That tosses N out the window. As well, it is too soon for 4G. So, we have to look to something else (if it is anything other than people making stuff up) for the meaning of "faster Internet".
IF this rumor is true, it is more likely that they are removing whatever roadblock that currently caps connectivity at 5mbit/sec. This may be processor speed, inefficient software, the interface to the WiFi chip, etc. etc. It's NOT the fact that they are using G Wifi.
It does make sense to remove this cap. You don't get THAT much faster a connection via WiFi currently than you get OTA (at least in a big city with good 3G). Which makes iPhone WiFi somewhat disappointing. I can see a lot of interesting applications opening up, say, in an Enterprise setting, with faster WiFi connectivity. But that doesn't require N.