Average home prices rose in March compared with February in most of the 20 cities in a Standard & Poor's/Case Shiller survey out today - the first time in seven months there's been a gain.  This report adds to the growing evidence that the worst of the five-year housing slump appears to be over.

"It gives some indication to both to what happened during the housing boom and how the bust may be unwinding," says David Blitzer of the S&P's index committee.

But there are many local variations in the 20-city home price index.  Some metropolitan areas are in far worse shape than others. In three cities - Atlanta, Chicago, and Detroit - annual rates of change declined in March. The other 17 cities saw improvements.

"The number of cities declining was lower than it had been recently. The number of cities hitting new lows was lower than it had been recently and except for a couple of places we see substantial declines, still we're beginning to see more stability in the overall numbers," says Blitzer.

Across the country average prices in March were still more than 2.5 percent lower than the year before and down 35 percent from their 2006 peak.  That's why nearly a third of  homeowners owe more than their properties are worth.