Interesting idea; just taken by what you wrote as intro.
The blue layout of the site isn't bad, the content needs to be centered into the middle of the page though you're sitting "way out left"
I have not signed up for the simple reason. You have not given me any reason to do so. Free is a good term,...but also a term that HEAVILY overused. Why should i give your site/game a shot? Show me what i'm going for, or what i'd miss if if DIDN'T sign up. Demo, screen shots, ability to preview the game and see others play while i can't play until i registered, etc. You've put out a nice starting point, now i'd suggest you revisit it and simply ask yourself; if i didn't know anything about the game, is the design or explanation enough for me to sign up?
Decide yourself and take it from there.