I recently conducted a workshop in the English Language Institute on using Dropbox to back up course materials and share them with students effortlessly. See the original workshop here:
Dropbox is a free website and computer program which enables you to easily back up files to the Internet and access them from any computer. You can also use Dropbox to help you publish files to the Internet for your students to access. This document provides instructions and tips for setting up and using a Dropbox account for these purposes.