Very interested in this, from everything I know about it thus far. (And I only recently learned of Aaron Staton's involvement; not a bad likeness, that.) Red Dead Redemption was the first of the Rockstar Games I'd bothered to play, and other than one other excursion, that's the extent of my experience with the sandbox form. (The Godfather game drew me in on the basis of the license.)
We'll be getting a trailer on Thursday, and it looks like a website as well. There had been one previously, but it looks like they probably took it down for the time being. I'm sure we'll get links to both here in two days.
Here's an older trailer from '06, which gives us a lot of atmosphere but certainly no gameplay. (That isn't to say that we'll get gameplay on Thursday.)