Microsoft SkyDrive give 7 GB of file storage on the Internet, with the possibility of requesting 25 GB
There is an App, (a program) that provides easy sync between a folder on your computer and your SkyDrive account. It can be used as usual through the web but you have to upload each file individually. The app is in the background. You can not continue with the works. Recommend reading this article that describes more closely. For backup, I recommend Mozy. It's not free but much better for backup.