GRNET (Greek NREN - http://www.grnet.gr) Network Topology Tool is a Googlemaps mash-up with topology, traffic and optical network info along with points of presence.
It[HTML_REMOVED]s built on top of Django templates along with Dojo and Google Maps API (v2).
Data is serialized into JSON from the Django backend. From then on JSON is fed into Dojo dijits and GoogleMaps markers.
A short webcast manual can be found here: http://www.youtube.com/watch?v=B7cFmu_oAuI