Is there "news" here. T-Mo wants to do everything it can to stem the loss of customers to carriers carrying the iPhone. No matter how large the AT&T payment is/was, they can't switch over (upgrade?) their network overnight. Trust me, I'm a TMo fanboy and, reading this, I didn't say Wahoo!
RobbieRunner brings up an interesting point. I currently am BB on TMo and have long enjoyed the pro-rated $19.99 (or close thereto) turn it on/off BB international service. YES, I know it's not "data" (e.g. web surfing) but it satisfied me - emails (that's what BB does) and BB chat (ibid). For web, I've always gone Wifi or local sim. I have to admit, as much as I've "wanted" an iPhone on TMo, I never thought about the loss of such a plan if I switch to an Iphone on Tmo.
Will they offer a similar email only plan with caveats/warnings out the bum to turn off apps that go to the web (via the international cell data network) and stay away from web apps, web surfing, etc. I sure hope so.