bk - here's my suggestion - do not use the words 'invest' and 'emini futures' in the same sentence or breath. When you trade futures, you are trading VERY AGGRESSIVE and HIGHLY LEVERAGED products. These are NOT your buy and hold mutual funds like you may be used to.
First step is to educate yourself. Be careful, there are many co's out there that will prey on newbies like yourself. Do your homework first.
Here's some FREE info out there:
http://www.cme.com/edu/
http://www.cbot.com/cbot/pub/page/0,3181,1130,00.html
You could spend the next few weekends reading and reading. And you need to.
Lastly, I am not a fan of daytrading futures in a retirement account. Not only is it a pain in the butt to get the account opened to trade futures, it costs more and I don't condone daytrading your retirement funds (no matter the size).
Good luck!