International Space Station as seen from Adelaide at 6:59 pm on the evening of July 19 looking south. The ISS will look like a bright dot, not the shape in the image (click to embiggen).
On July 19 (Australian time) the space shuttle undocks from the International Space Station.
That evening Australians have an excellent opportunity to see the historic last pairing of a shuttle and the ISS. We will see the ISS and the shuttle only 6 seconds apart, the two crossing closely across the sky.
Where and when you will see them is highly location dependent (although it will be early evening between about 5:30 and 7:30 pm), you will need to check CalSky and Heavens Above for predictions for your location. The East Coast ISS passes are generally short before the ISS and shuttle enter the Earth's shadow, so you need to be get the time correct.
The ISS and Shuttle are also visible on the 20th, but they are three minutes apart, and won't be so dramatic (although from Adelaide, they pass close to Antares).