Frequent reader, less frequent poster and #6 from Melbourne (Geelong to be exact!)
Whilst it's not huge, it's certainly growing. Silicon Beach is a community pushing technology innovation in Melbourne (and the rest of Australia). You can read a little more about it here: http://melbourne.siliconbeachaustralia.org/about-2/ and here: http://www.rosshill.com.au/article/silicon-beach-melbourne/
Sydney here, although going back to Tokyo for summer. (Reference for Melbourne residents: http://en.wikipedia.org/wiki/Summer)