The i phone comes locked under the suscriber identifiation module (SIM) so can only be used with the AT&T SIM cards.

After the release of the i phone a hacker in US developed a software to unlock the i phone and can be used under any of the of the GSM networks.

The IUNLOCk name software is available which unlock the i phone.So any sim card can be inserted and run on your iPhone

But as published a article by apple computers saying that the one who unlocks the i phone illegally damages the i phone permenantly and can not be recovered.The i phone once hacked will not be able to update the i phone software 1.1 with many new features.

It was also published that the i phone unlocked will damage its warranty as it broke its license agreement.So if tommorow a new version is available you wont be able to upgrade it

So friend beware of such software and dont break your i phone warranty

I request you not to jailbreak your iPhone