Boyum pointed me to this video, which gives a mostly-complete overview of what happened.
There will probably be costs to switch SIMs on the next change (to new plans), and at some point there will probably be incentives to attempt to push out the old plans (probably in a few years if they get to the point they want to drop GSM over TDMA completely). That's nothing new though, as the point of all that was supporting the two networks. This time it's just a name change so it shouldn't create any technical requirements on the phone end.
Copyright ©2000-2008 Jeremy Mooney (jeremy-at-qux-dot-net)
Yeah, that's about how it all happened. I was there when there was an AT&T Wireless and had to go through the purchase from Cingular. Those were the good old days... or maybe not.
What's going to happen to the people who are still AT&T Wireless customers and never converted to Cingular? Are they going to have to pay to convert from AT&T Wireless to at&t?