Many large companies are now ramping up their open innovation efforts to better bring in outside inventions that they can use. And open innovation groups are increasingly using online tools to reach out to prospective inventors. Kraft Foods provides a good example of this with their Innovate with Kraft website. It provides guidance regarding some of the types of innovations they are looking for, with an easy submission process. Inventors learn that submitted ideas must be shared non-confidentially and that compensation will depend in part on what the inventor owns. If a patent or copyright needs to be used by Kraft, then there will be compensation to the owner. If a submitted concept is not protected by a patent or copyright, Kraft, at its discretion, may choose to reward the submitter with up to $5,000 - but it's clearly much better if your concept has a patent behind it.
Disclosure: I've done some work with Kraft and really like the company and its people. And that's why I hope you'll use their Innovate with Kraft site.