You can also download the HD trailer, get details about the game, etc from all the big gaming sites as well as speciality GTA sites like GTA4.net.
I've been quite anticipating this day and I have to say, the trailer doesn't disappoint. It's more atmospheric and serious than I was expecting, but I don't think that necessarily signals a big shift in tone for the actual game. Mostly I'm relieved that this is going to be the GTA that I know and love, not some crazy thing in an exotic locale.
Seeing Liberty City again is like coming home, to be all overly melodramatic about it. I've spent hundreds of hours there and look forward to seeing its next-gen incarnation. Actually I still hold out hope that GTA IV is going to be more than just an improved version of the same geography from the "Universe III" incarnation, that like GTA: San Andreas it will include some surrounding countryside and another city (or two). But even if it doesn't I now know that "Universe IV" is going to be someplace I'm very, very interested in visiting.