All of the previous reports of Michigan playing Alabama at Cowboy Stadium in 2012 were corroborated by a pretty credible source... Nick Saban:
It hasn't been announced officially yet, Alabama coach Nick Saban said tonight on his radio show, but he announced it anyway: Alabama will play Michigan in 2012 in Cowboys Stadium in Arlington, Texas.
The original title of the linked source on al.com is really poorly written because it makes it seem like Michigan is also playing Alabama in Atlanta in 2013 and 2014:
Tide will play Michigan in 2012 in Dallas and in Atlanta in 2013 and '14
My excitement was subdued when the article said 'Bama will actually be playing ACC opponents, which makes sense considering the annual Atlanta game is usually apart of the ACC/SEC season kickoff. Anyway, a Michigan/Alabama match up at Cowboys Stadium is going to be amazing. Unfortunately, it's almost two seasons away. I guess we can put our excitement and the impending hype, which will be a lot, in our back pockets for now.