You're afraid others will steal it? IMHO, I think this paranoia can be harmful. Yes, if you talk to people, there is a "chance" that someone will steal it. This is a risk. But I think you need to take that risk, because the benefit of researching your market far outweights this.

So get out there, talk to people, find out if your idea is SO GOOD, that people are willing to pay for it. Hell, see if they'll pay for it now!

Good luck!