Truly free - does that include web host charges?
FrontPage includes a guestbook template - this requires FrontPage
extensions on the server, and often becomes very attractive to spammers.
If your host supports asp or asp.NET and Access or MS SQL server, or
supports PHP and mySQL, then you can write your own guestbook feature,
including some protection from spammers.
Or Google for "asp guestbook web application" without the quotes
(change asp to whatever your host supports).
