Beyond the proposed 2007 release, not much is known about this project yet in terms of cast, crew, or how closely it's going to stick to the source material. Will it mirror the book, or take things in a new direction akin to how the games have splintered off with each iteration? It's not clear yet.
Two things that are clear, if IMDb is to be believed, is that Zack Snyder is to direct with Hong Kong action movie legend John Woo in the producer's chair. Though usually recognized for his directorial prowess (Face/Off, Broken Arrow, Once A Thief, Hard Boiled, Mission Impossible II), Woo is no stranger to the producing role. If he can bring a sense of tension and over-the-top excitement to the Rainbow Six movie without making it all run-and-gun action violence nonsense, we could be in for a real treat.
I also hope Woo's experience and style filters into that of relatively new director Zack Snyder. They only thing he's done so far that I've seen was the recent remake of Dawn of the Dead, which I thought was pretty blah. Then again, as a big fan of Romero's original trilogy, it was an uphill battle to impress me. Some liked it, some did not. Thus, it's not a clear indicator of what we should expect from Snyder's take on Clancy's universe. Well, unless Team Rainbow is trapped in a mall shooting zombies. If they go that route, count me out.
All in all, I'm still pretty pumped to see what happens with the movie. The whole anti-terrorism thing is still pretty hot right now, and if done right, the movie could serve as not only another fine entry for the series that is bound by no medium, but also a sort of timestamp for Western consciousness and values. Lofty goals, yes, but you never can tell these days what our entertainment will amount to.