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Long long ago, I did port my number from a Sprint subsidiary to Cincinnati Bell with no trouble. I think there was some law somewhere which allows you to port your number to whomever you please.

The phone stores in my section of the world have some very sharp people working in them. The guy who I talked to about the iPhone at AT&T gave me some very good and straight answers. I got the impression that the Apple Store was of the same caliber, too.
 
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