Matt Wright's Guestbook
Guestbook allows you to set up your own comments page. From there, visitors can add entries to your guestbook and they will be displayed with the most recent at the top and scrolling down or vice versa. Other options include the ability to limit HTML in the entry, link to e-mail address with mailto tag, use a log to log entries, redirect to a different page after signing, e-mailing whenever a new entry is added and much more.