The most useful link is the government link http://www.ofheo.gov
for info on trend. It is amasing that the so many people want to live in the Las Vegas area while the Bay Area and Southern California housing are still hot while the economy stays cool. It would have been nice if we had purchased real-estate properties in those areas a few years ago.
If you want to find a home or exisitng market condition (viewed by the local real estate agents), try http://www.homeseeker.com