How do I pitch a software development idea to a company without giving away the idea?

For example, a video game for which I have developed a crude prototype.

Get a nondisclosure from the company. Make sure you've documented your program and ideas. Filing for patent will provide some protection.

patten it then tell the world
if anyone steals it and makes millions you can sue them for every cent that they have then you will become rich by doing nothing

I recommend checking out the US Copyright's information circular about computer programs -- see link below.

Hope that helps! I wish you much success & happiness in all your ventures!

Write down your idea/concept. Go to an patent lawyer who specialises in intellectual property. Get what's called a "prior idea". You and he/she sign your write-up. That's your record that you've had the initial idea. Then do a trademark search. If your lawyer is any good, he should then present you with a packet of all patented and trademarked ideas/products that resemble yours. Then file for a trademark protection. That's the least you need to do before going to a company. Better yet, get patent protection.

A friend of mine went to a company with a product sample, but without a patent. The company signed a non-disclosure agreement and a year later ended up throwing the identical product on the market, mildly modified (actually just a bit larger) and this thing is now on sale everywhere. Be very careful when dealing with companies. Get legal protection first or it's fair game for all. Better yet, get a worldwide patent.