LD I've been looking around a bit at adding a guestbook to a website...

generally adding a guestbook requires some html form building and some scripting (programming) to make it work. But many webhosts offer a guestbook as a part of their hosting package, i.e. they provide the scripting for you and install it on your account.

Looking through tripod I found this option under the "tools">"site addons">"guest gear" menu http://www.idexter.com