The folks at GameSpot have put a HALO preview together that details its history, gameplay, and other facts that have been floating around for some time. They call HALO the most anticipated game for the XBox and go on to say that it seems leagues beyond its competition, and its graphical polish, even at this early point, is very enviable. In regards to multiplayer, they had this to say:

We're sure, however, that Halo's single-player experience will duly compensate for its lack of online multiplayer capabilities--at least until the net-play-enabled PC version is released.

Check out the two page article. GameSpot's insight is always interesting.