Here’s a great little wiki article in the How To section of Wired.com. It talks about backing up your data as a Mac user. It’s extremely important to back up all your data, but most of us don’t learn this or follow through and actually do it until we’ve learned the hard way. The hardest part is purchasing an external hard drive with tons of space on it – at least the same capacity as the drive you’re backing up. Next you’ll need back up software. Time Machine is probably the easiest option because it comes with the Mac operating systems as long as your Mac has Leopard 10.5 or later. Check out the article for the details. They also list several alternatives to Time Machine and they also mention some online options for backing up your data.