Actually, game companies are NOT looking for ideas / drafts.  Just like writers, directors, etc. companies usually have _plenty_ of ideas already, more than they'll ever have time and funds to make.
If you're interested in getting into the games industry, Computer Games magazine has had a few columns on it, they may be online a 
www.cgonline.com.
Creating mods/levels for existing games is the best way to be an amateur game designer if you're not interested in paying your dues / working your way up in a game company.