How to sell a video game idea?

fobsta writes: "Do any Slashdotters have experience of selling video game ideas? I'm an artist whose programmed a rough as nails demo and animated a trailer to explain my concept. Obviously I think it's fun, it shows promise and my friends think it's cool. Who should I pitch the idea to? Existing video games companies, venture capitalists or what about those dentists that financed the Amiga? Are they still around? Having had a previous idea hijacked and received no reward for it whatsoever how can I prevent this happening again?"