Office of Federal Housing Enterprise Oversight OFHEO House Price Index. Tracks changes in the price of single-family homes across U.S Census Bureau divisions and 50 states and district of Columbia. Includes indices for Metropolitan Statistical Areas and Divisions, and other aggregates.
http://www.ofheo.gov/HPI.aspx - details

The S&P/Case-Shiller Home Price Index tracks changes in residential property prices in 20 metropolitan regions across the United States, includes composite indices that aggregate prices across the regions. Published monthly. A broader quarterly composite, the National Home Price Index,tracks single-family homes across U.S. census divisions.
http://www.homeprice.standardandpoors.com/ - details