Get your iPhone officially unlocked - for FREE - via iTunes

problem: Your iPhone is SIM locked

Your provider had your phone locked when you took on your contract... now you want to use a different SIM but it doesn't work.

solution: Ask your provider to unlock the phone!

It really should be very simple and FREE. For example o2 in the UK provide a online form for their customers and they'll unlock the phone within 14 days. This probably works for more than just iPhones too. Read more about o2's process on their site.

What is the catch? As you can imagine, there is likely a minimum contract term that needs to be fulfilled with most providers or at least they might claim that there is. Most countries have laws related to SIM locking and it depends on the providers and countries stance on such laws. Read more on SIM locking on wikipedia.

I went through the o2 process with a family members iPhone and it was totally painless. They quoted 14 days but it took less than 48 hours. A picture of the official unlocking in iTunes!

The process went like this:

1. Googled iPhone unlocking, found Olly's post linked below
2. Went to o2's site and search for unlocking etc
3. Found the unlocking FAQ article on o2's site
4. Filled out the unlocking form (dead easy)
5. Received the SMS from o2 that the phone had been unlocked
6. IMPORTANT: Inserted non o2 sim in to the phone
7. Powered the phone on
8. With an computer connected to the net, sync'ed the iPhone with iTunes
9. After a brief wait, the iPhone received updated carrier programming and the new SIM was operational

citation:

A big thanks and props to Olly Farshi @ giga om for sharing his knowledge and experience on this topic.