Adam - Go to the Orange shop! OFCOM have ruled that all mobile phones MUST be unlocked by the carrier by request of the owner, either when asked, or at least 12mths after purchase. If O2 can do it, Orange have to aswell! It's not the network provider that actually unlocks it, it's Apple. In my case, I bought a PAYG sim from O2, so I was now an O2 customer. So I filled out their form, and they take the info to Apple in California, who unlock the baseband on their database using the phone's IMEI number. Then, when you plug it into iTunes (after the database has been updated) with a sim from a different network, iTunes sends the info back to Apple HQ to check if it's ok, and Apple's database tell iTunes yes, the phone in unlocked, and iTunes unlocks your baseband. Mines working perfectly on T-Mobile now, with no sign of a Jailbreak of soft unlock in sight!

B19 JUB - unless you used software to preserve your baseband and bootloader when you were on 3.1.2, then 3.1.3 will totally overwrite it, meaning you have no way of unlocking it untill the Dev Team come up with a work around. Apple are not dumb to this anymore, and work VERY hard to get one step ahead of the Dev's, which is why I decided, after two years of owning an iPhone that was Jailbroke and soft unlocked, to go down the official route...