Melbourne, home to the 2006 Commonwealth Games, is a city of world-class events, including: a non-stop program of film and food festivals, renowned dining, major art exhibitions and musical extravaganzas.They've now padded it out a bit more, adding trams, and making it a bit more useful. (Before it used to be just Melbourne's rather minimalistic railway network, limiting its utility to tourists who are entirely unfamiliar with the city.) Still, without actual street maps (which their packages for some other cities, like London, Amsterdam and New York, have), it's not quite as indispensable as the editions for those cities.
Those wanting street maps of Melbourne on their handheld can make do with a JPEG viewer and scans of the 1966 Melway, which should be mostly accurate for the inner suburbs, give or take a few drive-in theatres and the odd freeway.
* that's "the map viewer named Tube", not "the program for viewing London Underground maps"