I have an innovative idea that I want to put onto the market, but I still have to develop the idea into a product.
I know a few companies that have the knowledge I am looking for.
What is the best option to handle this?
Start by talking with them and gauging interest. Just because you think it is a great idea does not mean they will want to invest time and resources into your idea. How much equity and/or cash they will want to develop your idea will depend on their level of interest.
Terms of the contract can be determined when you have more information.
Google Apps includes a knowledge management solution (wiki) and Google docs, both of which work well for sharing information. (http://www.google.com/apps/intl/en/business/index.html )