Sometimes, a Microsoft product exists without much fanfare. Such is the case with Windows Live Sync, a free online file synchronization program that compliments their SkyDrive service. This service offers a convenient way to share files between computers (PC or Macs) whether you are at work or at home.
David Pogue at the New York Times has written up a nice column on it: http://pogue.blogs.nytimes.com/2010/03/11/microsofts-free-sync-service/
I encourage you to read it and backup your files today.