Gmail as virtual hard drive
Turn your gmail account into a free online drive to backup your files, with Gspace firefox add on. It works by storing your files as emails. Even though you can do this yourself, Gspace provides ftp like interface.
As Gspace stores files as email attachments, they are limited to maximum size restriction of Gmail which currently is 20MB. As using this extension might be in violation with Gmail's TOS, you may create a dummy account for this purpose. So, go ahead and try it today.