Rather than explaining to my students how to enable the 'LatLng Marker' (Settings --> Maps Labs --> Enable LatLng Marker), I would like to just give them a link with the marker enabled. Is it possible to do this?
I don't think there is an easy way to do this. Because the page uses AJAX you can not just use the URL of the Save Changes button from Google Maps Labs like in the old days.
Your best bet would be to tell your students to log in to their Google account and change the setting once. The setting would be saved for the following sessions.