There are a few metasearch sites that cover australia:
IWantThatFlight.com.au
adiosu.com
cheapflights.com.au
I prefer the first one, its coverage of cheap domestic flights can’t be beat. They will even let you enter details of flights you would like, and will send you an email when it becomes available. It shows a list of cheap airfares on the homepage and also caters to overseas with a cheap international flights page. Give it a go!
