Apple this past week started selling factory unlocked iPhone 4?s in the U.S. Though Apple has sold contract-free iPhones in the U.S before, they were still locked to AT&T. This is the first time Apple is selling factory unlocked iPhones, which will allow users to use a SIM card for any GSM carrier. Below is the product description from Apple’s website: If you don’t want a multiyear service contract or if you prefer to use a local carrier when traveling abroad, the unlocked iPhone 4 is the best choice. It arrives without a micro-SIM card, so you’ll need an active micro-SIM card from any supported GSM carrier worldwide. Apple is selling the 16GB iPhone 4 model for $649 and the 32GB model for $749, that means for a premium of $450, you would have the freedom to use it on any GSM carrier. As pointed out before, the iPhone 4 will work on T-Mobile’s voice network but doesn’t support T-Mobile’s 3G network, which means it will only work over its slower EDGE network. Apple also made it a point to clarify in their FAQ section that an iPad micro-SIM card will not work with the unlocked iPhone 4. Only the GSM model of the iPhone 4 is available for purchse without a carrier contract, while the CDMA model is still tied to a Verizon contract as of right now. Despite the high price, the factory unlocked iPhones are still popular among international travelers who may need to frequently switch SIM cars to avoid the high international roaming charges. As a quick note, in case you aren’t aware, in addition to factory unlocked iPhones, carriers in some countries also offer authorized unlocking for an additional fee or may have some other requirement. You should checkout the Apple Knowledge Base article to find out if your carrier offers authorized unlocking. Are you planning to buy an unlocked iPhone 4? Do you think it is worth the premium? Let us know in the comments below. As usual, stay tuned by following us on Facebook, Twitter and/or by subscribing to our RSS Feed. Authors: