Earlier this morning, Apple began selling unlocked versions of the 16GB and 32GB iPhone 4 for $649 and $749 respectively. It's a steep price to pay for a phone that's otherwise heavily subsidized by wireless carriers (a 16GB model has a retail sticker price of $199.99 at Verizon), but hey, freedom isn't free. What's the upside of this GSM-only supported phone that requires you to buy an active micro-SIM card from a wireless carrier? It's not the greatest thing in the world but bloggers are pointing out some benefits. 

"The big attraction is, of course, being able to take the phone abroad and switch MicroSIMs to your heart's content, an experience that most other nations are already well accustomed to," writes Vlad Svavo at Engadget. In the past, American iPhone owners traveling abroad had to cough up "exorbitant international roaming fees," notes Chris Rawson at TUAW. For Rawson, "not being chained to AT&T for two years has to be the biggest [advantage]." Still, the only other major GSM-supported wireless carrier is T-Mobile and its 3G network is incompatible with the iPhone (so no data plan). "That said, if one really wants to buy an iPhone 4 for use on T-Mobile, there is now an officially supported means for doing so," reasons Ina Fried at All Things D. And having an officially sanctioned means to unlock your phone is something iPhone users have been seeking since the product's initial launch, notes CNET's Don Reisinger. "Over the years, several unlocking tools have been made available to people who wanted to break from the grasps of AT&T and try out T-Mobile in the U.S. Last August, for instance, the iPhone Dev Team released an unlock solution for the iPhone 4, called 'ultrasn0w,' that allowed users who had jailbroken their iPhone 4, iPhone 3GS, and iPhone 3G to bring the device to another carrier," he writes. "But those who wanted more official means of unlocking the smartphone have been forced to wait it out in the U.S. while other consumers around the world had their pick of Apple's unlocked devices." Besides that, Fried points to a couple other benefits. "It also might have some appeal for someone that is still under contract and just got a new phone, or perhaps someone who has lost or damaged their device."