you have to do for yourself.
you need sound advice from someone who has been there, and you need to listen to it. defend your corner, argue your point, but if you can't convince someone who's done it, don't think they must be wrong.
some ideas just won't make it in the open market, and yours may be one of them. a solid business is more than just the idea, and you need to be able to see how the business will work.
but if you can do that, the potential rewards are enormous. 