The best book I have read in terms of understanding trends and indicators is 'Mastering the Australian Housing Market' by John Lindeman, former head of research at Residex.
Also, in relation to the queries about historical data, you might find this interesting info about Residex found via
http://www.onthehouse.com.au/onthehouse_holdings/.
"Residex is dedicated to providing quality information on the real estate market to government, financial institutions, valuers, real estate agents, accountants, solicitors and individuals.
The company collects data from various Government Departments and Real Estate Agencies. The data is compiled into a unique database and today Residex would have information on almost every house in Australia.
The age of the data varies, for example Residex holds data in Victoria as far back as 1865 and constructs indices from that date to today. In New South Wales, Residex holds data as far back as 1901 and Residex generates indices from that date. In other states the data extends typically back to the 1980's.
The unique Residex database cannot be matched by any public or private organisation in terms of accessible historical data and completeness.
Residex provides information on all aspects of the real estate market, not just relating to price, but also rental yield, growth in prices, analysis of market movements, mortgage design, financial transaction structuring, raising and placing of funding facilities, loan risk profiles, statistical consulting, price estimation and research.
The company is consultant and adviser to state and federal governments on housing related issues including the development of financial instruments to provide funding for housing needs."
Cheers
Jen