Recently, I have upgraded my jaibroken iPhone 4 to iOS 6.0. As well, was able to unlock my non-contract phone with remarkable services from http://www.officialiphoneunlock.co.uk/. Official iPhone Unlocking Team is a magical team, after I paid them around 35 USD, within 10 hours, they sent instructions back to me, to connect to itunes and unlock phone permanently at apple server. It happened just as a miracle. Now my iPhone is free from tethering or jailbreak. I love the new avatar of iPhpne 4.
When iOS6.0 was installed. The baseband got changed. Ruling out any interest/possibilities of jailbreak further. i wanted to officially unlock with AT&T, USA. As my iPhone is elgible for unlock. I have lodged a unlock request with bill copy to AT&T customer care. used this link for official unlock request http://www.att.com/deviceunlockstatus However, they rejected the unlocking request stating that the bill copy as "Faxed documentation is ineligible or not received".
This iPhone 4, I am using for the 2 years. Was brought by my friend from Louisiana apple store. 32GB costed me around 750 USD. Though it was a non-contract with AT&T career. Expectedly it got locked to AT&T USA network. I was able to activate the new iPhone and did a jailbreak successfully without changing the baseband by using DiTS contacts SIM.
Though the iPhone 4 was very useful for my activities, I had problem of tethered jailbreak. Specially when I used to travel to my native. the network would go lost, it would never restore until i do the Just boot. I always carried a cable and redsn0w in pocket.
Now with iOS6.0 & phone unlocked, the phone looks new. No more "Just Boot". Thanks to Official iPhone Unlocking Team for a nice technology break.
As the Apple affiar is still on, i am waiting for the iPhone 5. Naturally, factory unlocked. If you are coming from US. Get me one. :)