stock.xchng – good variety and quantity, with clear licence terms; just note that ‘premium results’ (commercial products) appear at the top of search results, so scroll down a bit
Our Community Photo Bank – Australia and community-specific images free for non-commercial use under a Creative Commons licence; lots of great ‘real people’ and authentically Australian shots
Flickr advanced search – this popular photo sharing site can help with more abstract concepts as well as images of your local area; tick the box Only search within Creative Commons-licensed content
Wikimedia Commons – public domain and freely-licensed educational media content (images, sound and video clips); often has both contemporary and historic images on a place or subject
Picture Australia – massive library, great for specialist images, but getting permission to publish can take some time