I was wanting to attend and I printed of the forum to register and it said you had to be in the "industry" and that proof would be required.
I got this from their website:
"E3 is a trade-only event and is not open to the general public. Individuals who are not able to document their direct, professional affiliation to the interactive entertainment industry are not qualified to attend. The Management of E3 2004 reserves the right to deny any applicant admission."
I would really like to attend but I guess that I will not be able to unless I can make up some good fake documentation
I don't know if CES has the same requirement or not, I may try to go there, besides it is in Las Vegas