Google Transit provides step-by-step directions for travelling between two addresses by public transport.
The Transit Layer on Google Maps is intended to identify public transport facilities near a particular location.
"Think of a virtual metro map on top of Google Maps - even when we don't have itinerary planning available, we want you to be able to see public transit options that are available," said product manager Raphael Leiteritz.
"Our goal is to be able to offer transit information as an alternative to driving directions wherever possible."
The cities covered by the new Transit layer are (take a breath!): Belo Horizonte, Berlin, Bordeaux, Brasilia, Cairo, Capetown, Caracas, Chicago, Copenhagen, Dallas, Dortmund, Duisburg, DÃ¼sseldorf, Ekaterinburg, Essen, Frankfurt, Genoa, Guadalajara, Hamburg, Helsinki, Johannesburg, Kazan, KÃ¶ln, Lille, Lisbon, London, Lyon, Madrid, Marseille, Medellin, Mexico City, Melbourne, Monterrey, Montreal, Munich, Naples, Nizhniy Novgorod, Oslo, Paris, Perth, Portland, Porto, Porto Alegre, Prague, Pretoria, Recife, Rennes, Rio de Janeiro, Samara, San Francisco, Santiago, Sao Paulo, Seattle, Strasbourg, Toulouse, Tunis, Vienna, Warsaw.
Coverage in Melbourne appears patchy in that clicking on a tram stop shows the routes that it serves, but doing the same on a railway station provides no additional information such as the line it is on. And we could find no sign of bus routes.
But then much the same con be said for London: the Underground network is shown with the names of the lines serving each station, but clicking on a regular station does little more than tell you "yes, that's a station." Bus routes are not shown, and bus stops only appear at the highest levels of magnification.
When you do click on a London bus stop, you're sometimes presented with the route number, destination, and upcoming departure times. And sometimes all you see is a description of the location.
The Transit layer is still a work in progress, but it's no less welcome for that.
Please read on for the latest information regarding this story.
UPDATE: Google now says the inclusion of Melbourne was 'inadvertent'.
"However, our users tell us that they're keen to see Melbourne public transport information on Google Maps, so we'd love to incorporate it as soon as possible and are working towards this," he added.
The list of cities shown on the Google Lat Long Blog has been revised to exclude Melbourne.
When iTWire checked on Friday afternoon, the Transit option was no longer available when viewing maps of Melbourne.
Some tram lines had been removed from the maps but others were still visible. Even where the lines had been removed, the stops were still shown.
Asked to clarify his previous statement, Shilkin said "Neither the Transit layer in google maps or Google Transit are available for Melbourne yet."