Also, just some more tips...
If your drive is larger then 120GB (i reccomend anything larger then 80GB) you cant just set it as a slave drive. You will need an ATA PCI Card to handle the drive's size. In turn on boot up you will see a new DOS screen searching and connecting to the new drive.
And for those buying a new drive dont get anything less then an 8mb cache and try to get one that is 7200 RPM (unless your getting a Maxtor 300GB drive which is only offered at 5400 RPM {but a 16mb cache})