There are several reasons to want to know how to unlock iPhone 4 for free. Usually it is just so that it can remove the lock a certain carrier put on it. Unlocking the iPhone allows it to be used on any carrier not just one. There are a few reputable programs that charge to unlock cell phones, but it is easy to do it for free too; and just as effective. Not long ago regulatory officials stated that it is not illegal to unlock your cell phone since it remains your personal property.
The first thing you will need to do is to go to the website http://www.blackrain.com and choose the type of operating system you are using to sync the iPhone with, either Windows or Mac. You can download the software from this site. Once it has successfully downloaded run the program. Then plug the iPhone 4 into the computer using the USB cord and click the tab for “make it rain.” The software that is necessary to jailbreak the iPhone 4 will be installed on the phone. You will be prompted to click OK and then the program that is now on your iPHone will unlock it.