If you own the Samsung Galaxy S3 or Note 2, then you may want to unlock it. Unlocking is basically the process of removing the one carrier restriction that is placed on the phone when you buy it. This then allows you to place any sim card you have in the phone and still enjoy complete useability. Apart from allowing you greater flexibility in terms of which carrier to use, this process increases your phone's resale value as well. The method that will be shown is completely free. Check out the video below courtesy of Daveen Jay and if you have any questions please comment below. One more thing, this process requires the use of Android Jelly Bean 4.1.1. If you have a later version, you could always downgrade the software and upgrade again after unlocking.
*Image Courtesy John Biehler