A teenager in New Jersey has unlocked Apple's iPhone so it will work on networks other than AT&T's, including those in other countries.

George Hotz, 17, said he has unlocked the phone and was using it on T-Mobile's network in the United States. Apple launched the eagerly awaited phone exclusively on AT&T's network in June, and immediately faced criticism for how resistant it was to any modification.

Apple's iPhone is unlike most other GSM cellphones in that it cannot be easily opened to swap SIM cards.
(Associated Press)

The iPhone works on Global System for Mobile telecommunications (GSM) networks, which more than 80 per cent of the world's wireless carriers use. With a typical GSM phone, the user can open it and swap the subscriber identity module (SIM) card provided by the carrier for one from another operator.

The iPhone design, however, prevents easy access to the SIM card, and the device is wired to prevent non-AT&T SIM cards from working.

Hotz has posted step-by-step instructions on his blog on how to open the phone and disconnect the wiring so that any SIM card will work, which means it can be used on any GSM network in the world. In Canada, Rogers Communications Inc. is the only GSM network operator.

"That's the big thing," Hotz told the Associated Press.

He warned on his blog that the process is not simple, includes soldering and runs the risk of damaging the iPhone. "You are warned," he wrote.

Hotz is selling his unlocked device on eBay, with bids reaching more than $2,000 US mid-day Friday.

A cottage industry selling unlocked iPhones could spring up in the absence of the device's availability in other countries. At least one other website, iphonesimfree.com, says it has unlocked the device — this time using only software, without any soldering. A message on the site says it will soon launch the software commercially.

Apple and Rogers have not commented on whether they plan to launch the iPhone in Canada.