The man in black fled across the desert, and the gunslinger followed.
Ain't It Cool has an early review of the first issue.
If you're not a Dark Tower junkie, have no fears with this one. They've taylor made the first of the 7 issues to be an introduction to this world. The book does begin with the titular gunslinger, Roland, pursuing the Man In Black, just as in King's first book and focuses on Roland's childhood coming of age.
My understanding is that over the course of this mini-series we'll be getting the story of Young Roland's first tests, which were detailed in WIZARD AND GLASS, the 4th book in the series. There is a promise that we'll see events just hinted at in the books, such as the events leading up to the fate of Roland's childhood friends Cuthbert and Alain and the much hinted at battle of Jericho Hill, where Gilead fell and the world began to fall apart.
Can I tell you how stoked I am? I am stoked.