If your equipment is from North America then yes you will need an adapter as the Australians use a 230 volt system.
it will but to charge it you will need an adapter to work in diffrent voltage of Australia
I believe they would but Australia uses different electric plug.
For Brazil, you will need a Type N power adapter.
For Chile, you will need a Type L power adapter.
Yes! you need to use a power adapter as well a plug adapter in Egypt from the UK.
For England, you will need a Type G adapter for your electronic devices.
For the UK, you will need a Type G plug adapter.
To use electronic devices in the UK, you will need a Type G adapter.
For Argentina, you will need a Type C or Type I plug adapter.
You should be able to log on to Xbox live just fine with a US Xbox in Australia, by using and ethernet connection, or buying the Wireless adapter. Some games bought in Australia may not work on your US Xbox, you will need to buy games that do not have region encoding, so they will work on any console. Go this address for a list of compatible Xbox 360 games. http://forum.xbox-sky.com/xbox360_regional_compatibility_guide/ You will need to buy an adapter for the power outlet. These can be bought on Ebay for about $3 US.
For Indonesia, you will need a Type C or Type F plug adapter.