There are a few really good theatre history websites but these are the homes of some of Australia's greatest theatre historians. ( myself not included.) As I am based in Sydney, these are basically Sydney sources.
Australia's greatest Circus Historian- Dr Mark St Leon- www.pennygaff.com.au
Kent Blackmore- Sydney Magic Historian- www.sydneymagic.net
Leann Richards (me) History of Australian Theatre- www.hat-archive.com
Stage Whispers magazine- Current and past theatrical information- www.stagewhispers.com.au