Ustream, Engadet etc. will also have live coverage of the event...The ATV coverage is probably the best though...I'll probably have both running as I like the cat.
If they show it live, then I'll be using my Apple TV (which I am having delivered today! ) Also, I think they may be doing a live video stream on their website. If not, The Verge and Engadget always do really well with Live Blogs.