unlock an iphone (to use on another network)

[DubFan]

Does anyone here have a good method for unlocking an iPhone 3G to work on another network?

We have an old iPhone 3G which was on o2, but want to get it to work on 3. Has anyone managed to unlock an iPhone without a full jailbreak preferably, or used a service to unlock one?
There seem to be a few services advertised online, but you never know whether it's going to be worth the money or not.

Cheers

[damien010685]

At the end of a contract 02 will unlock it for you Speak to 02 you will need an 02 sim card in it for you to be able to do it .... I think theres even a form online but i would just phone them... I did it years ago to my old 3gs that i used to have

[DubFan]

The iPhone is well out of contract, it was my brother inlaws first, then he gave it to us when he upgraded.

Will see if o2 will do anything.

[Jay]

Anyone with a Galaxy S3 can follow these steps and have it unlocked for free. 
http://forum.xda-developers.com/showthread.php?t=1839200

IF you do follow those steps, you'll need to put the original EFS file back in place before any OTA updates, otherwise they'll fail from what I understand, bear that in mind as the Jelly Bean update is due within the next week 

[DubFan]

Well chaps, success.

First I tried the online form on o2's website (here if anyone is interested), but because the phone originally belonged to my brother in law, they couldn't process it without confirmation of security details from him.

So I got the security details required, then got onto the o2 support Guru chat this morning and half an hour later I got an email saying it was unlocked.
Then all I had to do was insert the non-o2 sim and connect it to the computer for iTunes to verify it as unlocked.

Job done and for free.

[damien010685]

Well chaps, success.

First I tried the online form on o2's website (here if anyone is interested), but because the phone originally belonged to my brother in law, they couldn't process it without confirmation of security details from him.

So I got the security details required, then got onto the o2 support Guru chat this morning and half an hour later I got an email saying it was unlocked.
Then all I had to do was insert the non-o2 sim and connect it to the computer for iTunes to verify it as unlocked.

Job done and for free.

Nice 1 mate