file management system

hi all, I am looking for a file management system. Does anyone know if such a thing exists? The goal is to make a web site with computer graphics resources. The features we would like to find in it would be these if possible: - the possibility to upload files - the possibility to check the uploaded file (Fileinfo is available on our server) - the possibility for the uploaders to refer informations and key words on the file they upload - the possibility for the uploaders to introduce themselves in a quick description of them and their work - the possibility for the uploaders to chose the license in which their work will be available (copyright or copyleft) - the possibility for the visitors to browse in the files available (date, type of file, key words, author, license, popularity of a file, etc..) - the possibility for the visitors to post reactions and discuss about the files, and to rate these. - we're looking for such a system as Free software (GPL for example) - if all those feteares are not available in an existing system, we will add those, but if such a system do not exist, is there people interested in the same features to develop it with us or just helping with testing and feedback? Cheers++