NSW. This link leads to the Maps and Photos section of the NSW Department of Lands website. You can order maps on-line, or get and endless amount of detailed mapping information for NSW.
South Australian Trails. A guide to South Australia's Walking, Cycling and Horse Riding Trails.
Victoria. A link to the maps and images section of the Victorian government Land website.
Western Australia. WA Government site with free downloads.
Google Earth. Try this website if you've the time to look at the world from your desktop.
Bikely. I don't know why it has this name, but it's a site with the aim of sharing ride information. Around the world...