Microsoft is now offering a free 25 gb online storage service called Skydrive. All you need to start is a Live account.
The interface is kind of sluggish, you can only add one file at the time and there is a 50 mb file size limit.
However, there is a free software called
Gladinet Cloud Desktop.With that software you can transfer multiple files, folders, subfolders, create backup-sets etc.
The Gladinet software adds an additional drive, z: in my case, you can easily access from the Explorer like it was another partion on your computer. I managed to get fairly OK transfer speeds around 1mb/s with my 100mbit internet connection.
25 gb is not much, but its another option of backing up important data in case you should run into problems. It is really a neat solution considering that it is free.