On Sunday, AT&T let go of its SIM-locked hold on iPhone users, allowing them to unlock their handsets for use with other wireless carriers.To unlock an AT&T iPhone, the device needs to be off-contract. For most users, that means owning the phone for more than two years, but you can also get out of an existing contract by paying an early termination fee. Also, your account must be in good standing with AT&T to be eligible for an unlock.Unlocking an iPhone allows you to use SIM cards from local wireless carriers when traveling abroad, which are usually cheaper than paying for international coverage from AT&T. You can also use the phone on other GSM carriers in the United States, such as T-Mobile, although data speeds will be slower, and you can’t use an unlocked AT&T iPhone on Verizon Wireless or Sprint.I have an old iPhone 3GS that’s no longer in day-to-day use, so I decided to give the unlock process a whirl. Here’s what you need to do to unlock yours:1. Look up your iPhone’s IMEI numberGo to Settings, then “General,” then “About,” and you’ll find the IMEI number listed near the bottom. Write it down. If you’re on a family plan, you’ll also need the last four digits of the main account holder’s social security number.2. Contact AT&T by phone, on the web or in personDial (800) 331-0500, or 611 from an AT&T phone, or visit the carrier’s online support page for Wireless Support Chat. I tried both methods at the same time, and got through by phone first. When the system asks what phone number you’re calling about, you can give your current number even if you’re unlocking a different phone.3. Tell AT&T you want to unlock your out-of-contract iPhoneProvide your IMEI number and be patient during the unlock process.. You’ll also have to provide an e-mail address, where AT&T sends the unlock instructions.4. Wait for AT&T’s e-mailFor me, the e-mail arrived a couple minutes after getting off the phone, but other users have reported much longer waits. PCWorld’s Ed Oswald was told to wait eight days, and an Apple Insider forum-goer was told to wait five to seven business days.5. When the e-mail arrives, back up and restore your iPhone in iTunesOpen iTunes on a computer that’s connected to the Internet, then plug in your iPhone. Sync it with iTunes, then right-click on the device under the “Devices” column on the left side of the screen, and click “Back Up.” Once that’s finished, right-click on the device and select “Restore from Backup.”If all goes well, you should get the following message in iTunes: “Unlock Complete. Congratulations, your iPhone has been unlocked. To set up and sync this iPhone, click Continue.”At this point, you should be able to insert SIM cards from other carriers, but check to see if your iPhone still has its SIM card tray, which covers up the thin slot at the top of the handset. If it’s not there, you can buy one on Amazon for about $1, plus an eject tool if you don’t want to use a paper clip.For me, the unlock didn’t go smoothly. After backing up and restoring my phone, iTunes didn’t confirm the unlock. I tried doing a full restore, but that sent me back to the iPhone’s activation setup, which wouldn’t go through since I don’t have a spare SIM card and tray for the phone. I called AT&T back, and they said my unlock failed, and that someone would follow up with me in a couple of days. I’ll let you know how that turns out.My advice: If you’re planning to travel abroad and would like to use your old iPhone, unlock it well ahead of time. Better to sort out any potential headaches now than get stuck without your precious smartphone.
