When I was walking past Southbank when I saw some Parkour being practiced. I watched for a while and spoke to the instructor after the informal lesson was finished. He’s a professional instructor with the Melbourne branch of the Australian Parkour Association  and he sometimes gives free advice to newbies that he meets on the street (in this case a group of 6 teenage boys).
From the web site it seems that the standard lesson fee is $15 for an indoor lesson or $10 for an outdoor lesson – with a $5 discount for members of the Australian Parkour Association , which is really cheap for a 2 hour lesson! APA membership costs $10 to join plus a $50 annual membership fee.
It’s worth reading the ParkourPedia information about the “spirit/philosophy” that is Parkour . It’s interesting to note that there can be no official Parkour shows because if you do it for anyone else then it’s not Parkour – so much for all the Parkour videos on Youtube. Also another issue with the Youtube videos is that Parkour isn’t about doing the most dangerous things you can possibly survive in an urban environment, it can be practiced in country areas and isn’t supposed to be unreasonably dangerous.
The outdoor Parkour lessons start near the Arts center in the middle of Melbourne and presumably some of them go past Southbank as it has some interesting things to jump over. So it’s worth watching out for people jumping over various obstacles instead of walking around them. They may not be doing a Parkour show, but it’s in public and anyone can watch.