Teacher Planet has a thematic links page for Australia - http://www.teacherplanet.com/resource/australia.php You can find lesson plans, art activities, clip art, and other information related to Australia.
AtoZ Teacher Stuff - many additional links to lesson plans on Australia http://www.atozteacherstuff.com/Themes/Australia/
An online picture book: http://www2.lhric.org/pocantico/australia/about.htm
More links to fun adventures in Australia: http://www.activityvillage.co.uk/australia_links.htm
Make a digeridoo - an Australian musical instrument - http://www.kinderart.com/multic/didgeridoo.shtml
Links for arts & crafts activities to support Australia