Bashiok made a short post yesterday answering a question about the PPV streaming feed of Blizzcon, which you can purchase and view online (without requiring a Direct TV subscription/dish).
The official page to purchase this feed is here, and the FAQ has some useful info. Much more useful is this unofficial FAQ I found in the WoW Europe forums.
Note that you may view Blizzard’s streaming feeds of the Starcraft,Warcraft 3, and WoW tournaments from Blizzcon for free; but you’ve got to pay/subscribe to see the video of the Blizzcon panels and other features. Also note that the “live” streams are actually on a one hour delay; so if you’re watching and you want to instantly hear the news about (hypothetically) the WoW expansion, the 4th D3 char, and other new stuffs, you’ll want to check news sources like this site, or our Twitter feed, which we’ll be updating via cell phone directly from the show floor (wifi is blocked during panels, in the convention center).