I found more file sharing services:
In order to avoid sharing email with students, Blogs, Wikis and Google Docs are alternate ways students can submit work instead of written assignments. Another option is to use a file sharing website.
FileStork https://www.filestork.net/ Teachers create a "stand alone" request which will allow you to post an upload link on your blog or website. Visitors use that link to upload a file. People that upload files to your Dropbox through File Stork do not have access to files within your account.
Drop Box https://www.dropbox.com/ Is a service for file sharing....it is free. There is a video you can view in order to learn how to use it.