Hello splodge, I can put you in touch with my own company (that i work for) and a few others, Electornic Arts/Mindvision if the game has mass potential. First things first though, outline your idea, produce a base story, how it works, what platforms you'd hope it to be played on and it's target audience, that's enough for starters. Secondly, be prepared to flog your idea, research it thoroughly. Thirdly, if your not comfortable, telling anyone your idea, get someone who is.
Lastly, be prepared for a slating, the world of gaming can be bit cut throat, but that said if your idea has good potential you should be ok.