You have multiple options to catch E3. You can watch it live on Spike TV, which for me (basic Comcast cable) is Channel 60. Its at 12:30pm ET (9:30 PT) However, if you can not watch it live there will be multiple ways to access E3.
Options:
-Gametrailers will have live coverage of all of E3
-Spike obviously, im not entirely sure if they will have coverage online. I clicked on the E3 link and it took me to game trailers so perhaps they are working together.
-G4
-Xbox Live, if I’m correct will have live coverage as well.
As you can see, you have many chances to see E3! 
Also they repeat it after a while on Tv.
P.S. I posted this on a thread already but I figured I should make my own just to compile all E3 sources into one place.
PLEASE let me know if I missed anything. I’ll update as much as I need. I hope I was able to help you guys out who were clueless Feel free to ask any other questions!
Austin7934