The official Australia Post web site - very useful for recent, current and forthcoming issues.
See all Australia stamps in the StampWorld free online catalogue.
Recent news about Australia stamps, from StampNews.com.
An illustrated checklist prepared by Australian National Botanic Gardens.
Publishers of the Australian Commonwealth Specialists' Catalogue.
Wikipedia listing of people depicted on the stamps of Australia, with links to biographical data.
Wikipedia page providing a useful overview of Australian stamps and postal history.
Online catalogue of Australian stamps.