The floodgates have opened for iPhone owners who want to do all those things Apple would rather they not. Jailbreaking was declared legal, a jailbreak for nearly every Apple device was released, WiFi-only apps found their way onto 3G, and now a "carrier unlock" has been released for iPhone 4.

The carrier unlock only works on jailbroken phones, but as the video at the end of this post shows, the entire process only takes a minute.

The terms "jailbreak" and "unlock" are often confused, but mean very different things. A jailbroken phone allows the user to run third-party apps that are otherwise not approved by Apple. An unlocked phone allows the phone's owner to choose a different carrier. Apple has an exclusive contract with AT&T to offer the iPhone in the U.S., meaning iPhone owners cannot chose their own carrier. This "carrier unlock" just released by the "iPhone Dev-Team", allows users to switch to the carrier of their choice.

To unlock your iPhone, it must first be jailbroken, which just became drastically easier with this week's release of a browser-based jailbreak that literally takes seconds to complete. Once the phone is jailbroken, the carrier unlock is available in the Cydia app directory.

"Ultrasn0w", as the carrier unlock is called, can unlock iPhone 3, 3Gs and 4. The following video from @TechTechManTV gives a succinct how-to on jailbreaking and unlocking your phone.

As always with something like this, it is strongly recommended to backup your phone with iTunes before even beginning the process. And take note that although this is all easily reversible to factory defaults, Apple has warned that jailbreaking your phone could void your warranty.