well, pretty much follow the Tom's 'how to' article posted earlier in this thread.

If you are not accustomed to doing these kinds of computer procedures, the fun part starts at the point you wipe the hard drive (IE> format the hard drive). Once the hard drive is formatted, your computer no longer has all the normal smarts with which you can manipulate it with. It still has the low level smarts that you can use either through your System BIOS as well as whatever technician's tricks you know from experience. Once the hard drive is formatted, it needs to be partitioned. If you only want to run a single OS then a single partition is fine, but you should read up a bit on the particulars of the flavor of Linus you are going to load just to be sure it does not have any advice or caveats about how to partition the drive.

Once the drive is partitioned, you'll need to configure the computer so it will know it has a CD Rom drive. Also, it will be really helpful if your system has a floppy drive AND you have a bootable floppy disk with some basic DOS and Disk utility commands. Floppy drives have become somewhat rare these days due to the proliferation of CD/DVD drives and USB peripherals. Having one will be most helpful if something unexpected happened AFTER the hard drive was formatted and before the CD-Rom configuration is done. To repeat, once you've formatted, you no longer have the normal ways to manipulate your computer. The BIOS that comes with newer systems have gotten pretty good at giving the user decent amount of control over a system that is lackign an OS, so if you have a newer system, the BIOS may help you get past any snags that occur with formatting/partitioning and getting the CD Drive back up. Once you get the system to acknowledge it has a CD-rom working, then the difficult part is over since the computer now has enough smarts once again to get additional smarts from the CD you use to load Linux.