I'm putting 'SugarSync' through its paces over the weekend. It's a piece of software that keeps multiple PCS in synch with each other - in short, you change a file on one PC and the changes are copied across in real-time to other PCs on your network such as your laptop. Great for when you're out and about and don't want to have to manually copy files you've been working on back to your main PC when you get home.
The software even puts a version up there on the 'net (password protected of course) that allows you to get at your mission-critical files even if you've left your lap-top on the train!
If that's not clever enough, it will also give you a unique email address that allows you to send attachments to ALL your networked PCs.
.and it'll even upload them to FaceBook if you want to.
It's not free, but the prices are very reasonable - actually there IS a free version if you only have a few files to back-up and it's a good way to try it out without handing over any dosh.
So far, it all seems to be working fine!