Personal Technology -- New Services Give You Reliable Ways to Keep All Your Files Updated "These file-synchronization services aren't free, and they do take a little effort to set up. But once they are up and running, the effect is like magic. Within minutes, or even seconds, after you have added or deleted or altered a file on one of your computers, the change is perfectly replicated on all your other machines.
There are three main contenders in this budding field. One, called Groove, available at groove.net, is owned by Microsoft. It's mainly designed for collaboration work in big corporations. Two others, BeInSync and FolderShare, are aimed directly at consumers and small businesses."
$60 to $100/year -- nice annuity business.