Tagwall class  

this tagwall class works with both text files and MySQL databases.

Price: Free

   sbook  

sbook is a very simple guest book with many new functions.

Price: Free

   GeoBook  

Features: Filters Support, Emoticon (smilie) Support, Deny Unwanted IP Address(s), Control Panel, FULL Template Support.

Price: Free

   12react.php  

These scripts give the possibility to write a reaction to other web pages and as such can also function as a guestbook. It gives visitors the possibility to fill in some personal data and a comment. The administrator can block, delete and approve the reactions. Either before they are placed or afterwards.

Price: Free

   BeanWebb Guestbook  

This is a free guestbook you can add to your website. Includes a full admin script allowing the administrator to Add, Edit or Delete Records. This script requires PHP and access to MySQL.

Hosting Requirements: PHP
Database: MySQL
Price: Free

   Sulata Guestbook  

Sulata Guestbook is a small and attractive PHP and MySQL based guest books. It uses a style sheet to manage the page layout. The lovliest features are emoticons and easy administration.

Hosting Requirements: PHP
Database: MySQL
Price: Free

   phpBook  

PHP/mySQL Guestbook. Features: Location Templates - Floodprotect - IP-Logging & banning - Browser-Logging - Smilie's Database - URL-Code - Dirty Word Filter - E-Mail Notify - Web-Admin-Panel - Moderator-Function.

Hosting Requirements: PHP 4.x.x
Database: MySQL 3.23.x
Price: Free (GPL)

   YapGB  

YapGB is a free guest book system written in PHP.

Hosting Requirements: Unix, Win NT
Price: Free

   DigiOz Guestbook  

The DigiOz Guestbook is a PHP driven guestbook system that stores all the entries in a simple text file. It is very simple to install and use, and the header and footer files included with the script allow you to customize the script to blend in with the rest of your website.

Hosting Requirements: Unix/Linux, Windows
Price: Free

   KISGB  

An advanced PHP guestbook program that does not require sessions, cookies, or an rdbms. Can be Public or Private through HTTP Authentication. Message editing by User. Theme Builder included. Flood control. Private messaging. Flexible logging capabilty for tracking anything. Includes web-based password protected Admin functionality, along with email notification, ip logging, ip banning, bad word filter, smileys, allowable html tags in comments, next/previous, automatic link recognition, etc. Themes for controlling appearance that allow for background colors, images, animations, etc., and Multi-language support for 29 languages.

Hosting Requirements: *nix, Windows
Price: Free