Unlike most countries in the world, Aussies drive on the left. Unlike the UK, which is full of tricky round abouts, most large intersections in Australia operate using a traffic light system, which can make it a little less confusing.
When driving in Australia, you do need to ensure that you are correctly licensed and that you are aware of the road rules. Some basic rules are you need to stay under 0.05 blood alcohol, 0.00 if you are a new driver and on P plates (the first 3 years of driving) and to be aware of the speed limit. There are a lot of police and road traffic cameras on Australian roads, so don't be alarmed if you are pulled over for a random breath test. Speeding fines are issued for any speed over 3kmh (1.9mph) over the marked speed limit, so it is essential that you don't speed, or it can add up very quickly!
Australia has great roads and freeways that connect its cities and there are many interesting places to stop on the way. On popular routes (don't expect it in the outback!) you'll regularly find rest stops with petrol and take away stops to refuel your car and yourself. There are also many interesting towns to visit along the way, giving you an 'authentic' Australian experience.