By adjusting the S&P/Case-Shiller home-price indices—which were released Tuesday—for inflation, financial bloggers at the site Calculated Risk suggest that home values may be years away from a nadir.
Look at the length of the housing bust in the early '90s. It took over six years from peak to trough in some cities. If this bust takes the same amount of time, prices will not bottom in some cities until 2012 (or there about).
You can check out the chart here.