Well, the trailer is now available on YouTube (via U2.com):
Of course, this is just a 2D YouTube video, but the trailer has also been making the rounds in theaters showing other 3D movies, and from the testimonals of those few that have seen it, it's stunning. Don't forget, this isn't the 3D of red-and-blue cellophane lenses that we grew up with, this is high-tech stuff (I actually saw Alfred Hitchcock's The Birds in high-tech 3D, and it scared the crap out of me, I imagine viewing a 3d U2 concert will be a much more pleasant experience).
But I'd also like to point out that, even in 2D, this trailer looks to be shot and directed very nicely. I'm excited about it. Excited enough about it to be willing to take a trip out of town just to see it, when the time comes.