纽约时报报道，AT&T Will Unlock iPhones。

我们知道，在AT&T买的iPhone都是锁上的。也就是说，这个电话只能通过AT&T来使用。当然，你可以偷偷的Unlock, 但如果有个update,问题就出来了。现在有个好消息：AT&T Will Unlock iPhones。

AT&T has confirmed it will allow people to unlock their iPhones, which would mean that the phone could be used on other wireless networks. Most notably, it means you could have an iPhone on the T-Mobile network in the United States, as well as on other networks internationally.

There are some caveats:

1. Right now, unlocking the phone isn't reliably easy. One blogger reported that unlocking the phone took a visit to the AT&T store, a call to AT&T tech support, a visit to the Apple Store Genius Bar, and repeated restarts of the phone taking about 12 hours. Others in online forums have said they have gotten their phones unlocked in as little as a half hour.

2. Your phone's network speed may slow down. Although AT&T and T-Mobile are both GSM networks (as opposed to Verizon and Sprint which are CDMA) they use different frequencies. That means that if you choose to unlock your iPhone and use it on T-Mobile, it will run at sluggish 2G speed. Keep in mind that we are now up to 3 or even 4G in much of the country.

Where unlocking may make more sense is if you travel overseas. Instead of being hit with kabillion dollars in fees, you could take an unlocked phone and replace the SIM card (which is essentially the identity of the phone) with one from a European carrier. It looks as though pay-as-you-go SIMs can be had for about $15 online.

Changing the SIM is easy and doesn't require removing the back of the iPhone. Few people have noticed the well-machined drawer in the side of the iPhone, but if you look on the side of the phone opposite the volume controls, there is a pinhole opening. Insert a paper clip and the drawer will open to reveal your SIM card. Using another SIM will change your phone number while it's installed, but that's a small price to pay for much lower local calling rates.

That part, at least is simple.

 如何换SIM card?