AT&T has done a few changes that aren't so friendly for people (increasing the early-termination and changing the data plans.) Apple might have let them do it without objecting too loudly in return for "something".
My prediction is that like last year the "old" iPhone 3GS will drop in price to keep a low end model & keep putting pressure on all the other cell phone companies. But I think they may go REALLY low in return for those cell plan changes. Such as free (with a 2 year contract of couse.)
I've yet to be right, but who knows this time. We'll see next week.
(Update: so I'm 100% on my predictions! all wrong.)