Isnt that equivalent to buying a CALL (or PUT)? In this case there is no margin to be paid on futures position!
There are lots of strategies. Some risk free ones are,
1. Buy Futures, Buy PUT and short CALL (Same Strike)
2. Sell Futures, Sell PUT and Buy CALL (Same Strike).
Your profit in the first case is, CALL - PUT - (Futures - Strike). You need to take the trade only when it's positive (You've to make profits, dont you?). You can work it out for the second one. Your profits are going to be limited (very limited), just better than interest, and, is for Very large volume players.
BTW, your option on indices cannot be exercised as they are Euro type. Exercising an option is normally a last resort, as selling the option in the market will give you time value premium in addition to just the intrinsic value which you would get by exercising.
www.cboe.com has (or had? I havent looked at it for quite sometime), some good learning material on Options (Chicago Board of Options Exchange).