How to unlock my iphone which is on O2 network?

How do i unlock my iphone which is on O2 network?

Added (1). Its a 3GS model

Go to a phone shop and it will not cost more than £5

Use remote unlocking service to unlock your Iphone 3GS from O2. Get the service from the site http://www.simpleunlocking.com/apple-iphone-3gs/rs16wp9/, and unlock your mobile yourself using unlocking instructions which is given below:
Apple iPhone 3GS Unlocking Instructions:
1. Wait for us to send you an email saying your phone has been activated or remotely unlocked.
2. Install the latest version of iTunes.
3. Make sure your Apple iPhone 3GS phone software is updated to the latest version using the iTunes software.
4. Connect your Apple iPhone 3GS to iTunes with a NOT ACCEPTED SIM card.
5. Wait until iTunes detects your Apple iPhone 3GS.
6. Disconnect your Apple iPhone 3GS and reconnect it after 10 seconds.
7. Your Apple iPhone 3GS is now unlocked.

Use a Sim card from a network other than the network your Apple iPhone 3GS is locked to.

Hi, the best option would be to use an official carrier granted unlocking, but it depends on the network and country the iPhone is locked to. You can read more information about iPhone unlocking in the following article: http://www.fastgsm.com/en/page/how-to-unlock-iphone