You said the design is semi-complete, right?
Sending off a semi-complete design to a bunch of companies mightn't be such a great idea, even if you were to make sure your IP is protected. If it's only semi-complete, and it actually manages to get past the secretary, then the gurus could probably just use the bits of it they like most, go in a slightly different direction and steal the idea right from under your nose.
I would suggest fleshing it out a bit more, making sure to get it all down on paper.
Then develop some sort of presentation, possibly a prototype, and make sure you can explain why you think it's a new concept, and why you think it would make money.
Then get your legal issues in order.
Finally, whore yourself to as many companies as you can.
Others might have more to add to this.
Yes, the fleshing out part sounds smart, I've got about 5-6 handwritten pages containing the project, and from that i should be able to make a fair presentation. The only problem is that I've got absolutely no gamedevelopment experience, so i wouldn't know how a presentation like that would look like. Has anyone got a link to something similar, like a video presentation or even better: an actual letter to a developer.