I am going to have to join the people who say you have little hope, but instead of focusing on this, let's try to get you somewhere.
See if Microsoft has something like Google's Big Idea Challenge, which is available here:
Google
Study Microsoft's corporate structure and find out which department/person deals with outside suggestions. Most of the time, I assume, Microsoft reaches out to business that it sees potential in, but I am sure it is frequently approached by others.
If we assume that 20, 000 people (probably a very low figure) submit ideas on a regular basis, how can you make sure yours gets to the right people first? You have to come up with something brilliant and it shouldn't be pestering someone who works at Microsoft. Let's say I gave you Steve Ballmer's cell phone number, what would you do with it? I highly suggest you not place that phone call because you would only piss him off. He would hang up on you before you could a word in because he's heard these "brilliant" ideas many times before. Instead, come up with another idea. Networking might be a solution at times, but it is very unlikely to work here.
I used to give one of my supervisors ideas on how to improve business practices all the time, and she would never listen (this was at a well known company). If my direct supervisor immediately dismissed me without even taking the time to listen to what I had to say, why should a complete stranger at Microsoft listen to you? Good ideas are commonly ignored in the corporate world.
Suppose I connect you with one of the principal programmers of Windows Vista, why would he want to know your idea if it wouldn't make any difference to his paycheck?
Try these idea submission pages at Microsoft (not very relevant, but a place to start):
http://www.microsoft.com/globaldev/o...deaSubmit.aspx
Communities
If you go here, you'll find that there's a guy named John Beld who also has a "confidential" idea. Try contacting him:
Mark Bower : How To Submit Ideas and Suggestions for Microsoft Office Products
El Extraditable - The Extraditable.