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check out www.predictify.com --- might give you some ideas on how to make a buck (and what you are up against!)

Some guy I know is doing the same thing. This validates your idea but obviously also implies a bit more competition. http://www.hubdub.com/

And for anyone who missed this one lately ---> look at the stakes on this bet! http://www.longbets.org/362

also intrade.com is a full-fledged futures prediction market in ireland but may give some ideas.