E-mail providers often put a limit on the size of a file you are able to send as an attachment. In addition, students are often unable to move files from home to school and back again. You Send It, yousendit.com, is a great free service that can be helpful for you and your students when you need to move large files back and forth.
For students who are at home, all they need to do is to fill in their personal email address on the yousendit.com page, browse on the local computer for the file (up to 1 GB in size), upload it, and send the note to themselves. In a bit, they will receive an email with the hyperlink to click on to download the file. They should remember to copy down this URL before they go to school to retrieve the file. Then, they can simply visit the link and download the file. It stays on their server for up to 7 days. When at school, they can simply repeat the process and retrieve the file when they get home.
As teachers, you can use this to send large items to colleagues or also use it to move large files between home and school!