Look at the schedule.
Gaming opens at 8:00am. The viewing rooms open at that time as well. Registration will likely begin at 8:00, the vendor room opens at 10 from what I've seen, and opening ceremonies is at 11:00.
So, get there around 9 and you're guaranteed to get in. At the meeting we heard that more than 1000 people have pre-registerred, and there's usually the same ammount buying badges at the door. So as long as you're one of the first 1000 people through the entrance you should be fine!
Personally, I suggest getting there around 8am. The really intense locals will already be in line but even if you have to wait an hour you really won't be missing much.