Dave,
you don't really need to get an external chasis for it. Usually your computer has an extra cable to hook up another hard drive and the computer should recognize it when you turn it on. I did it a lot on my windows 98 and after 4 years, just got xp, so....teacher or student at your local college should be able to help you. SHOULD be really easy, but like I said, xp might be different.
hope you find out how...SOON!!!!!!!!