Dropbox is an incredibly useful free tool. It enables the storing of two gigabytes (or more) of files including text, photos, audio, video, and more. These files can be protected from others or shared with a group.
Here's an introduction to Dropbox:
Here's an explanation of some of the more advanced features including sharing:
More tips and tricks: http://www.brighthub.com/education/k-12/articles/86024.aspx
And, one more valuable tip - logon at http://dropbox.com/edu and verify your .edu address for yet another half gigabyte of storage! (and double credit for referring others)