Sharp,
You've come to the right place. Between Lance, mcurto, and the original poster of this thread you can't go wrong. Read this thread in its entirety.
I typically trade 1 - 10 contracts almost everyday. It all depends on the risk I determine the trade represents. Personally, I agree 100% with Lance. If you want a hard fast rule, trade 1 ZB contract per 10,000 USD. If you want to push it, trade 2, but never more than 2 per 10,000 USD. Especially at your stage.
Later, with the experience, if you are day trading exclusively, you may be able to push it further but then you are entering very dangerous territory. You can make excellent money trading 1 - 2 contracts consistently every day. See my journal for some insight on this. I think I wrote about excessive trading back in December of last year.
Granted you won't make Lance type money, but then again, you and I won't win the Tour de France, but we can win our local and regional competitions.