I'm not sure about movies, but I've heard of educators using Google Docs for classroom work involving presentations. Check out Google Docs for Educators.
I think some of the freeware mentioned in the discussion What freeware do you use for sharing large files with colleagues? provides storage for files. Let us know if any of these work for you. Great question!
I would use dropbox. You can use this service for free and get 2 GB of storage space. You can also subscribe and get a greater storage limit. Sharing the storage space with other users is easy and I believe that when you share the space with a new user, you get more storage space(not sure about that though). Check it out at dropbox.com.