If anyone would like to help build a list of notable Free Software orientated companies, consider contributing here:
http://en.wikipedia.org/wiki/Category:Free_software_companies
In Wikipedia, "Categories" are lists of articles that contain a certain tag. To add articles to the "Free_software_companies" Category, add this tag:
[[Category:Free software companies]]
to the bottom of an article on a company that fits the definition.
That article also has a discussion page: http://en.wikipedia.org/wiki/Category_talk:Free_software_companies
...which can be used to discuss which articles are appropriate and which are not. Changing the name of the category is another thing that could be discussed.
Note that the aim is to make it easier to navigate Wikipedia's free software related information - this isn't related to GNU Business Network.
Another part of Wikipedia that might be useful, or is a good place to start as a contributor, is the Free Software portal:
http://en.wikipedia.org/wiki/Portal:Free_software