No.
AT&T. But you can "unlock" an iPhone for verizon.
you can tbuy an iphone without at&t.....
You can request an unlock from the carrier that the phone is locked to. The carrier will not unlock your phone for free if you still owe them money on a contract, you should still give a try. I did some research and found this website http://www.freeunlock.us they claim to provide a free unlock for iphones as long as you share them on facebook, i also found http://www.unlockmd.com this is a paid unlock but it is the cheapest i found for AT&T iphones.
You can buy an iPhone without a plan, but you won't be able to text, call, surf the web, etc. I do not think that was his question , he want to know if he can buy a iPhone without a contract or a phone plan , the answer is yes you can buy one , you can buy it just about anywhere , the thing is you would have to get it activated by the provider , also it would need to be unlocked if not already , this means that it will work for any GSM carrier at&t tmobile etc , since you bought it outright without a plan that co should unlock it for you for free since you done that , most iPhones are locked to at&t from my experience , you have to call them and ask them to unlock your iPhone for another carrier , hope this answers your question
If your iPhone is unlocked, then yes, all carriers will work. But if it is locked to a certain carrier, then you will have to unlock it using a jailbreak.
There are some organisations that can do this for you, it is very difficult to do this yourself. It depends on which carrier the iphone is locked to. There is a site that can unlock every iphone for you, they are called stockunlocks and then your problem is solved.
A CDMA phone shouldn't need to be unlocked. It normally isn't "locked" in the first place, unless it is still under the original contract with Verizon or Sprint services. If it IS still under contract, it is illegal for you to use it on another carrier until you have finished your contract or paid your contract early conclusion penalty fee.
you can simply unlock your iphone 4s now a days. visit some website which provide unlock codes. See related link. Provide them the phone and carrier details, pay the little fee and get the code.
No. If you are running 3.1.3 (the latest firmware) on any iPhone, then you can jailbreak without unlocking. If you are on a firmware below 3.0, I think you can jailbreak without unlocking. I would like to add that I am pretty sure jailbreaking an iPhone is illegal because of your contract with Apple. Find me on YouTube: TheJailbreakGenius
Not without voiding the warranty
Not yet. WIND is trying to set a deal with apple but apple wont change their frequency. Untill T-Mobile gets the iPhone, WIND won't. I know it sucks
From iPhone 4 and beyond you can use simple software to unlock your phone. The 3GS is not able to unlock your phone unless you buy a special SIM card or take it to a different carrier