How can I find out if a web page has been updated?
Most of the time, web servers deliver information only when you
ask for it. Usually this is a good thing, but in some cases you
may want to be notified when a web page has changed. When you
want notification that a page has changed, consider using
URL-minder (URL is <http://www.netmind.com/URL-minder/URL-minder.html
> ), a web-browsing robot which will automatically notify you by
email when a page of interest to you has been updated.
World Wide Web FAQ