I have a billion dollar idea like iphone or facebook now what should i do?

I have created some thing now i know it has some potential. Where and how should i launch it. Now i don't want to sell it to companies for money but somehow be directly involved in it.

Destroy all traces of it so you don't get sued into the ground

Take a class in entrepreneurship.

Hire programmer (code urself if you can) launch yourself(selling company will bring hefty money than selling idea.

Implement your idea in the most approachable way, so that maximum number of people can approach you.
If you know programming it's well and good. If not then either learn or get a friend involved with you and implement your idea.
Where you should launch your idea depends on your idea, means what it is about, what kind of people it will be useful for.
Consider your self to be a shopkeeper selling something and now you need to boost your sales so what all you will do.

have a nice day
i'm a computer science programmer and a business man, if you need any help just mail me at "kakaggarwal@gmail.com".