Gamespot, IGN and G4 will all be broadcasting everything at the following addresses:
- Gamespot: http://e3.gamespot.com/live.html
- IGN: http://www.ign.com/events/e3
- G4: http://www.g4tv.com/e32011
In addition to that:
- The Microsoft conference will be broadcast on Spike TV, but apparently not on their website.
- Sony will be streaming their keynote to the PlayStation Blog
- And Nintendo's conference will be watchable at http://e3.nintendo.com/
...and if you're at work or can't watch a live stream for some other reason, most of the major sites and blogs are liveblogging it.