I know it's not op shopping, but as it's in the same spirit (finding good stuff cheaply), I thought some of you might be interested in knowing that the Garage Sale Trail is on tomorrow.
You can go to http://www.garagesaletrail.com.au/ to type in your postcode and see what garage sales will be on near you.
From the website:
"Garage Sale Trail is a program that enables the peer-to-peer exchange of assets, resources and money on a local level but with national scale. It happens all over Australia on one day, Saturday May 5th 2012"