You can head over to Apple's website to see if you're eligible for an upgrade to the iPhone 5 on Sprint, AT&T or Verizon Wireless. If you are, you can use Apple's site to pre-order the phone on Friday, or walk into a store and purchase it on Sept. 21. AT&T recently released a video that shows just how to go through the process. First, head over to http://www.att.com/iready or visit http:///www.att.com/phoneupgrade to see if you're eligible.

AT&T says it can only sell one device per line and that, if you have multiple family members, every person on your family plan needs to be in store with you if they also want to buy an iPhone 5. New or existing customers can choose between AT&T's existing individual plans or its new Mobile Share plans. Check out the video above for more information.