Outside of concerns regarding prices, billing and other service details, many customers apparently want to know if they can now purchase an iPhone through T-Mobile. The answer, of course, is no. Again, the acquisition hasn't occurred yet and T-Mobile doesn't have rights to Apple's handsets.
While on the subject of devices, it's worth noting that T-Mobile subscribers with 3G smartphones will have to purchase new devices if the buyout is completed. AT&T reportedly plans to reallocate T-Mobile's 3G spectrum to 4G, so current 3G phones won't have wireless broadband access.
That sounds harsh, but it shouldn't pose much of an issue. The deal is still subject to regulatory approval and by the time AT&T's changes are put into effect, you'll probably be using a different handset anyway. "There's nothing for [customers] to worry about ... it will be done over time," AT&T explained.