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I haven't watched the video, but normally you can port phone #'s after you've gotten the phone. So it would (or might) go like this:

1. Get iPhone w/new number.
2. Call up and have old number ported.
 
OH lol...i can't watch it because i'm at work..can you tell me? sorry 🙁

thats too bad!

in the video there is a step by step process of using iTunes to set up/activate the iphone.

on one step you select if you are current att customer or transferring from a different carrier.

Basically if you choose different carrier, then it asks you if you want to bring your old number over and you type in the old number. It looks pretty simple and the guy in the video says it will take anywhere from right away to a few hours.
 
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