Just after a few hours of the launch of iPhone 3G, the phone has been cracked and jailbroken, which allows the iPhone 3G to accept installation and running of third-party application programs. Now the iPhone hacking becomes complete with hacker manages to find a way to unlock iPhone 3G.

When sold, iPhone 3G is SIM-lock to tie the cell phone to official few selected mobile service carriers, such as AT&T, severely restrict the user from switching to another telco. Once the iPhone 3G is unlocked, owner can freely subscriber to another cell phone service carrier which offers much lesser subscription prices and usage fees.

Previously, iPhone 2G using iPhone OS 1.x (haven’t been upgraded to iPhone OS 2.0) has been unlocked via free software utility. The first unlock hack attempt on iPhone 3G running iPhone OS 2.0 that is successful is hardware-based unlock tough. The unlocking is achieved by Breno MacMasi, a Brazilian hacker.

The unlocking of iPhone 3G is similar to original SIM card hacks for iPhone classic, involving using a special SIM card that piggybacks to existing iPhone 3G SIM card. The additional SIM card uses one SIM adapter to simulate and forge a fake IMSI (International Mobile Subscriber Identity), fooling the phone into thinking it’s using an official and approved carrier.

Techguru shows the video clip that show the hack to unlock iPhone 3G with a fake IMSI SIM card does work: