"The big effects are likely to come next year,"

Marketwatch.com:

Home prices falling faster, Case-Shiller says

Prices down 3.9% in 20 major cities in past year

By Rex Nutting, MarketWatch

Last Update: 5:17 PM ET Sep 25, 2007

WASHINGTON (MarketWatch) -- U.S. home prices in major cities are falling at the fastest rate in 16 years, Standard & Poor's reported Tuesday.

For 10 major cities, home prices fell 0.6% in July and are down 4.5% in the past year, the fastest decline since 1991, according to the Case-Shiller home price index released by S&P. For 20 major cities, prices fell 0.4% in July and are down 3.9% in the past year, the largest decline in the seven-year history of the index.
[. . .]
The last time prices fell so much, it took more than eight years for home prices to return to their peak level.
[. . .]

Here are the 20 cities covered by the Case-Shiller index, ranked from worst to best:

Detroit, down 9.7%: Tampa, Fla., down 8.8%; San Diego, down 7.8%; Phoenix, down 7.3%; Washington, down 7.2%; Miami, down 6.4%; Las Vegas, Nev., down 6.1%; Los Angeles, down 4.8%; San Francisco, down 4.1%; New York, down 3.8%; Cleveland, down 3.6%; Minneapolis, down 3.4%; Boston, down 3.4%; Denver, down 0.7%; Chicago, down 0.9%; Dallas, up 0.7%; Atlanta, up 1.2%; Portland, Ore., up 3.8%; Charlotte, N.C., up 6%; and Seattle, up 6.9%

Rex Nutting is Washington bureau chief of MarketWatch.