A little; they do vary. Nowhere near as much as US accents.
With respect to major cities, Adelaide has the most "British" sounding speech. Melbourne's slightly better polished than Sydney, while Brisbaneites are more likely to inflect up at the end of sentences. Perth is suposd to be slightly different but it sounds like Queensland English to me. Haven't had enough to do with Darwinians or Taswegians to pick anything there.
Compared to most US speech, we rabbit on at nineteen to the dozen (but I seem to recall reading that we're slowing a little), and the speech is more slurred or "swallowed".
Country areas can be a little slower speaking, and perhaps more traditional in diction, but no real change in accent.
If I had to put it in a nutshell, we speak quickly, and many of us "pinch" our "a"s and "e"s, also inflecting up for emphasis.
TV and the 'net are imposing much more upon us, mainly in that Americanisms are significantly entrenched and have usurped many traditional expressions.
Aboriginal English is different again. Aside from a few would-be "niggers" (and I use the word to refer to people in the US who call themselves such in an act of defiant resolve), speech is slightly staccato and more emotionally flat in delivery. You end up paying attention 'cause they could be getting up you, having a lend, or just talking - hard to tell sometimes!
:roll: I imagine this renders things clear as mud.
Adam.