It is possible to go from an original idea to a finished animated film entirely using free/open-source software, as illustrated here with examples from the "Lunatics!" project.

FilmFreedom.org is a new site we are creating as a portal for access to documentation on free/open-source production software, free culture business models, community, and free culture production projects, as well as original documentation and tutorial content, so you can learn how to use these tools yourself.