CloudDrive provides easy desktop access to 5GB Acrobat.com cloud storage
A more convenient way to do it is with CloudDrive, a small Windows application which provides drag-and-drop simplicity. It's similar to Gladinet and SkyDrive Explorer. Launch CloudDrive, drag in some folders and files, and let it handle the formerly tedious upload process for you!
Acrobat.com accepts just about any file type, so you should be able to drop in things like 7-zip archives, .mp3 files, or anything else you want to back up for free (like my Lego Digital Designer files). Just make sure you read the terms of service before you get started to make sure this is the right fit for you.
CloudDrive is a free download and works on Windows XP or newer.