Be Warned: Mr. Bubble's Worried Again - New York Times

Mr Irrational Exuburance himself, Robert Schiller has long been predicting the housing crash and its implications. He points to history in this nytimes article:

A history of Norwegian house prices that Mr. Shiller has found shows the same pattern. As does his index of American house prices, until the blastoff of the last decade. In chart form, it looks eerily similar to the stock chart from his 2000 book.

Even so, Mr. Shiller has little company for his radical notion that house prices could fall by 40 percent. Many economists say that interest rates are low enough and demand for housing in big urban areas is high enough to keep from prices from falling very far. Mr. Shiller himself confesses to some doubt.