There seems to be a lot of spin on that article. Quoting median prices of detached homes and then overall sales. I only trust data from reliable sources. This article data is from a Realtor who is citing a report made by the California Association of Realtors.
The below sales data is from Dataquick:
02/05: 3,442
03/05: 5,018
In 2005 there was a 46% Month-to-Month increase in sales. Price declines started in 2005.
02/2006: 3,035
03/2006: 4,367
In 2006 there was a 43% Month-to-Month increase in sales. No bottom in 2006.
02/07: 2,863
03/07: 3,218
In 2007 the Month-to-Month increase was 12%, Y-O-Y there was a decrease of 26%.
The median price for March was up, but the price per square foot was down. Interpret the data anyway you like. To me, there is no sign of a bottom yet.