Chartres: Cathedral of Notre-Dame offers photographs, diagrams, antique prints, and maps of Chartres Cathedral. And that's not the only virtual Chartres site: there's a tour courtesy of San Jose SU and a more elaborate tour (requires Quicktime) offered by the Art History department at Ithaca College. Among other things, Great Buildings features some 3D models (additional, albeit free, software required to view). Speaking of virtual experiences, you can walk the Chartres labyrinth (see here for a more technical description). And don't forget video, including this National Geographic short on the cathedral's architecture; you can also listen to the bells.