Re: look further
If you're worried about protecting the idea then I think out-sourcing the idea abroad is probably the last thing you want to do. Trying to protect the idea in one country will be enough work.
Talk to a solicitor about a Non-Disclosure agreement. You could build into that agreement a clause the prevents them from working in the same area, or launching a similar site for a period of say 6 months, or a year.
Finally, I wouldn't worry too much. In my experience companies that build websites see all sorts of "Next Big Thing" ideas. Some are good, some are bad, but you'd be surprised how little temptation there is to take one of the ideas and rip it off.
Good luck with it.
-Rd