Within hours of its launch last week, hackers managed to jailbreak the software on the 3G iPhone.

According to reports, the iPhone Dev Team, which also cracked the software on the original iPhone, hacked the handset to allow SIM cards from other networks to be used with the new 3G handsets and also with the first generation iPhone, which has been upgraded with the new software.

This hack could mean the 3G iPhone could be used on a pay-as-you-go basis before O2 officially releases its own non-contract plan later this year. It will also users upload unofficial, or even pirated applications to the device.

See also: iPhone Software 2.0 released