Box.net

Box.Net provides a way to backup files, share them, and even collaborate with others (collaboration comes with a price). Almost any type of file can be saved. You could create one Box.net account for every email account you have and end up with one gig to store music and another gig to store photos. This is an online service and access is available from anywhere you can connect to the Internet. Another part that's beneficial is being able to post files right to a website and if you decide to make the file public it is given a website address. There are no advertisements seen and the site prides itself on that. One gigabyte of space is free. Upload any type of file and multiple files at one time. The drag and drop function for adding files is handy or just upload through the browse and upload method. For those teachers that don't have access to their school files from home, this would be a great way to keep files, update them, and print them. Very secure and constantly backs up the files to provide redundancy. There is even phone support for paying members.
A weakness is that in order to join you need to include an email address. The only way to collaborate is to buy the professional account. File size is limited to 10 MB for the free service.
The price is hard to beat for 1 GB, free. It's $79.95 a year for 5 GB and $199.95 a year for the 15 GB. The most expensive plan also comes with 20 subaccounts to allow for sharing and collaboration.
A great application to the classroom is called the widget. It allows for pictures, video and audio to all be put within the widget, or box that holds it all. The widget can then be added to a website, blog, or wiki. It would be great to accumulate a few resources for students to use and place them within the widget to be used at a website, without having to add in all the code for each individual item or go back onto Box.net to retrieve them. This is a free way to backup files without having to buy a jump drive and access those files from home. This is more for the teacher to keep work safe and be able to access the work anywhere, which could lead to better preparation and better teaching.