I run a two-person web development business and have worked out of Adelaide for myself for 15 years. Always seems to be enough work around and a decent amount of variety.
The other SnappyCam purchaser I mentioned is an iOS/Android developer who is a sub-tenant in my office. We actually have a cheap, spare desk in this room at the moment if you wanted to visit and work for a while. Email me if you want to ask any questions.
Adelaide is good. Plenty of gov & defence work if that is what you are after, but I've worked here nearly 15 years and never done either (ok, my current place is quasi-government, but still..)
Guy behind me said "Hey, this is pretty cool. Have you seen... oh, you're looking at it already."