I was recently introduced to a service called DropBox. The site basically allows you to have an online folder where you can store up to 2GB of documents, pictures, video, etc. for free. You then have the ability to view the files from any computer where you can get online. I stared using it a few weeks ago and even have an app on my iPod Touch where I can view and upload files. It is pretty slick.
I use the service mostly to upload files that may need to access later, away from home. I might put some genealogy reserach notes in the file so I can get them later at the archives. I also use it to help transfer files from one computer to the next. Just upload them on one computer and download them on the next.
The service is free but you only get a limited amount of space, allbeit a fairly large amount to begin with. You can pay to upgrade the size of your folder but most casual users would not need to. I am not sure how secure your data is so I would not upload naything too acritical. As long as you are using it for light backup, file transfers and a little file sharing, you should not have much to worry about anyway.
If you want to check it out, you can follow this link: DropBox