AnvilBook.com - Here, you can sign up for a free guestbook for your Web site. AnvilBook.com guestbooks are easy to use and offer lots of features including time zone and date formatting and customizable body background, link and text color.
UltraGuest.com - Free fully customizable guestbook service with unlimted guestbook entries, support for RSS, spam protection, up to 3 custom fields and private messages.
Freeguestbooks.net - A great free remotely hosted guestbook service that's packed with a ton of useful features, including: a customisable guestbook interface, private messaging, user and IP address banning, usage of smilies (emoticons), entry editing, site recommendation, etc.
Smartgb.com - Here's a quality and well-maintained free guestbook service for Webmasters. Smartgb.com includes over 60 predefined themes to select from, so you can customise the guestbook to match your site.
123Guestbook - Free guestbook provider with tons of features, such as replying, editing and deleting messages, thank-you email, email on new entry, scroller with last message to put on your website, and lots more.
e Free Guest books - This is a good place to go if you're looking for a free guestbook for your site. eFreeGuestbooks offers remotely hosted, ad-supported guestbooks that are highly customizable. Features here include bad word filtering; IP and E-mail banning; new entry alerts and over 30 smilie faces to choose from.
Web Site Goodies Guestbooks - Click on the "Tools" link near the top of the page to access WebSiteGoodies' free guestbook service. Here, you can easily set up a guestbook that offers lots of features and can be customized to match your site.