If AT&T didn't drop every other call we make and have the worst data service we've ever used, we'd think twice about dropping this little hint. But we're about to unleash this with little guilt. Here's what you need to do to get Internet tethering on ANY iPHONE OUT THERE. Yes, even yours.
So without further ado, the 9to5Mac Tether:
There are 2 things at work here.
A. The iPhone 3 OS GM activates on any iPhone as long as it is a legit iPhone. (Not SIM unlocked and working on Tmobile in the US or Vodafone in the UK for example). If you are using your iPhone on AT&T in the US, it unlocks without issue. When you go to iPhone 3 you lose your abiity to Jailbreak (for the moment). More information on this here.
B. The first iTunes 8.2 Pre-releas
