If you want to monitor your web-based information resources and track changes to the pages before conducting that next class, consider using one or more of these resources (all require registration):
Change Detection [http://www.changedetection.com/monitor.html ]
Change Notes [ http://changenotes.com/ ]
TrackEngine [ http://www.trackengine.com ]
Watch That Page [ http://www.watchthatpage.com/ ]