Australian tax
From TaxAlmanac
TaxAlmanac is a website for US tax professionals, so we don't really have much information about filing taxes in other countries. However, click on the category "Foreign Tax" at the bottom of this page, as there may have been some prior questions about how Australian and US taxes interact. Also try "Australia" in the yellow search box to left.
Helpful links:
From the Australian Taxation Office About Us: The Australian Taxation Office is the Government’s principal revenue collection agency, and is part of the Treasurer’s portfolio. Our role is to manage and shape tax, excise and superannuation systems that fund services for Australians.
A page with "useful links to other government and tax-related internet sites": Australian Taxation Office Links.
On either of the pages linked above, see the menu to the left side of those pages for info on filing returns, working out tax, etc.