The most popular American operator AT&T began offering a service of official iPhone unlock for iPhone 4s, 5s, 5c, 5 & 4. You can request an official unlock for your phone at any moment by using the official service from iPhoneJailbreak-Unlock.Com. This unlock operation can be done just by entering your device’s imei code & connecting the devices with Apple iTunes software to unlock it.

The most popular American operator AT&TIn other words, now the users of locked iPhoens, can request for an official unlock iPhone through for their AT&T devices. Before you start, make sure that your phone is currently locked to AT&T carrier and your phone is not blacklisted in the Apple database.
Supported AT&T iPhones for this unlock:

Unlock AT&T iPhone 5S up to iOS 7
Unlock for AT&T iPhone 5C model
Official Unlock AT&T iPhone 5
Permanent Unlock AT&T iPhone 4s
iPhone 4 AT&T Unlock up to IOS 7

To Unlock your iPhone visit the official team’s website

http://iphonejailbreak-unlock.com/factoryunlockiphone/


How to Unlock AT&T iPhone for other sim cards:

Step 1: Go to Settings -> General -> About on your device, scroll down to the IMEI.

Step 2: Go to the official iPhone unlock website and select your original network (in this case you need to choose AT&T USA or enter your imei to check it).

Step 3: Provide your IMEI code (find in the first step).

Step 4: Within 24-72 hours you will receive an email to confirm that your iPhone is now officially unlocked.

Step 5: Now you need to follow instructions from the email, which includes a steps with the synchronization and restore process of the iPhone.

Step 6: Congratulations, you have officially unlocked iPhone now!

To date, this unlock method is the best solution for the iPhone owners that works perfectly with ANY firmware & baseband. In some cases, the “unlock complete email” can take up to five days. Don’t forget that this solution is legit & verified. The best feature is that your phone will be permanently fully unlocked for ANY network in the world.

After you completed this unlock procedure, your AT&T iPhone 5s, 5c, 5, 4, 4s is completely sim free and you can use it with other sim cards (T-Mobile, Verizon, Orange, Sprint, etc).

Tnx dude

Is dis process applicable to other carrier like sprint