One of the best features of Mac OS X 10.5 (and 10.6) is Time Machine. It's automatic backup software, built into the system, and it works really well. It's easy to set up, and you can forget all about it after that-- until the day you need it. You'll be very, VERY happy to remember it that day.
Hard drives aren't made to last forever. One of my customers found that out last week, when her iMac's hard drive simply stopped turning. The machine was only two years old! Replacing the hard drive was the easy part-- but, as my customer said, "What about all of my stuff?" Luckily-- or, really, good on us for thinking of this a long time ago-- we'd been backing up the iMac with Time Machine, and we were able to restore all of her stuff to the new drive. Years of email, thousands of photos of grandkids, a big address book, a full calendar-- all restored in a few hours and with minimal fuss. No one likes having her Mac break down but getting everything back feels pretty good.
If your Mac is on 10.5 or higher, and you want to start using Time Machine, you'll need to get a big external hard disk to store the backed-up data. You'll want something much larger than the drive you're backing up, because Time Machine keeps multiple backups of your stuff (multiple versions, from multiple days) and more hard disk space equates to more days of backups. Here's a link to a nice drive from Seagate, makers of the best drives around. This one's 1.5 terabytes, which is about 1500 gigabytes, available from Amazon for about $120.
Here's a picture.
So, you get the drive, you plug it in, you get a message asking whether you want to use the drive with Time Machine, you click the Yes button, and that's it. Easy. Depending on how the disk is formatted you may have to reformat it for use with Time Machine but that's not a hard thing to do. If you need a hand with that I know a guy but I think you can do it yourself.
Apple has a very nice article about Time Machine via this link. Worth a peek.
(Note: besides helping you recover from a major hardware meltdown, Time Machine is also great for when you need to get an older copy of a single file-- maybe the current one's become damaged, maybe someone threw it away, who knows. Time Machine has rescued me more than once, mostly helping me bring back trashed files that I didn't think I'd ever need again. It's quite the little safety net.)
