This information is already posted at Wikipedia as follows: http://en.wikipedia.org/wiki/Metrication_in_Australia
They use the metric system
Miles.
miles
meters
Meters
If it's a big town, then miles.
The same units that you use for length and distance. For example, the SI unit would be the meter.
inches or centimeters, I would use inches.
No. You would use different units of measurement. You would measure the size (circumference) of your waist (for trousers) in centimetres. You would not measure the distance to the moon in centimetres!
Kilometers
I would recommend that it would be tonnes because any other weight is usually used for food, distance, liquids, etc.
What measure of units would you use to measure the thickness of a phone book
kilometers