Newbie needs CAPTCHA help...

I get ~500 spam messages a day in my guestbook. It's just a dinky family website guestbook, but I'd like to try to add a CAPTCHA validation to it. I found some code online, but I'm a novice and I don't know where to add it.

Is anyone patient enough to walk me through this?

TIA!

Brooke

Take a look at this article -CAPTCHA Image

HTH,
Ryan