Amazon has just released a desktop client for its free online backup service, Amazon Cloud Drive for both Windows and Mac.
Google Drive Released Today
Today, Google officially released Google Drive.
SugarSync File-Sync/Backup Software
SugarSync is a unique file sync/backup solution, similar to Dropbox.
Mozy Backup Software
Mozy is a very powerful and easy to use backup solution.
Dropbox File Sync/Backup Software
Dropbox is a fantastic application.