Instructions
Go to the official PlayStation website and click on the "Contact Us" option at the bottom of the screen (See Resources). From here, you can send an email that shares your idea to Consumer Services or you can call Sony Computer Entertainment America at the phone number provided on the page.
Click on the "SCEA Job Listing" option to see available jobs at Sony. Look for a position that meets your skills, including game developer and creative writing positions. There's no better way to be able to share your ideas for PlayStation video games than to directly work for the company.
Look for video game tester jobs, which typically require at least a bachelor's degree and extensive experience in playing video games. These positions are extremely repetitive and require you to play a game over and over to find any bugs or defects in the game. Obviously, after testing the game, the developer will be interested in what you think of the game and will take into account any ideas you have for improving the game.
Earn a degree in computer science and learn to be a game developer. Find internships at major video game companies, like Electronic Arts, that develop many games for PlayStation (See Resources). Also with such credentials, PlayStation representatives will pay more attention to your ideas that you submit directly to them. Never solicit your ideas for free to PlayStation if you're a game developer. Offer to set up a meeting to discuss your game ideas.
Write a game design document to send to Sony's human resources first, which will be passed on to executives and developers if they're interested. This document should be a well designed outline that includes how your game will look, the tone and graphics used in the game, the gameplay and the user interface (See References). Be sure to go into as much detail as possible.