Australia's main phone networks:
|Australia's country code||61|
Long-distance calls (over around 50km) are paid by time on the call, with peak and off-peak rates.
Area-code boundaries don't always coincide with state borders; for example some parts of NSW use the neighbouring states' codes.
Numbers with the prefix 04 belong to mobile phones.
Either set up global roaming, or pick up a local SIM card with a prepaid rechargeable account on arrival in Australia. Shop around as deals vary depending on how much data or minutes you expect to use.