IahTexan.
Be a little careful with the distinction between domicile and residence, at least for tax purposes. I think that you will find that such a distinctionary concept is unknown in the USA. As I understand it, a country of residence is where you live and work. Domicile is a state of being, usually acquired at birth or through where your father was permanently living at that time. This concept is very, very, important in England and thus perhaps in Australia. In the UK you can be resident here but not domiciled. If such were the case you would then only be liable for UK income tax on any income, which was earned outside the UK, remitted to the UK. Australia may well have the same set up, given the number of Poms living there. In any event, if you are a US citizen; I believe that the IRS will want to tax you on your worldwide income, subject to any taxation treaty which might exist between the US and Australia. You would end up paying the higher rate anyway-of course. Thus, if the Australian income tax rate were higher than the US rate then the Aussie Revenue would give you credit for tax paid in the US before leviing their own, always presuming of course, that such a treaty does exist between the two countries. If it does not, I suppose that you could be liable for full whack in both places.
You might want to check out any double taxation treaty between US/Australia and also that country's domicile/residence setup, if any.
In the real world, I suspect that if you put your head down no one will notice, but I do know that you do want to mess with the IRS. Look what it did to Capone.
Very sorry about that last post. It should have read that you do NOT want to mess with the IRS
