Sure do. It's very simple. All you need is a 6pin to 6 pin Firewire cable just like the one that comes with the Mac version iPods.
Once you have the cable connect the two and start up the computer you want to use. Then start up the computer you want to get the data off of (the one you want to use as a hard drive) while holding the T key. This will put it in what's called Target disk mode. Basically it will convert that computer to an external hard drive.