URL-Minder: Your Own Personal Web Robot
http://www.netmind.com/URL-minder/URL-minder.html
Presents the URL-minder, your own personal Web robot, which retrieves your registered URLs regularly and reports back to you by e-mail when they change. The URL-minder also runs searches on Web databases regularly and lets you know when anything new that matches your search shows up. It also keeps track of the places you've been, so you can spend your time (and money) doing new things on the Web.