Developer Steve Troughton-Smith has managed to crack into the Apple iPhones Internet tethering preference pane then connected his Apple iPhone to his Apple Mac through a USB and then used the Apple iPhone as a modem.
Unfortunately Steve doesn’t have a clue just how he managed it; he set a message via twitter saying “To all: I have no idea how I did it. Sorry! I was hacking around with APNs in the Carrier.bundle itcc file.”
Those iPhoners who use a jailbroken iPhone are already privy to tethering, however when iPhone OS 3.0 hits, Apple will kick out all jailbreakers, that is until the iPhone Dev Team jailbreak iPhone 3.0.
Source — pcworld