In 2008, the US lost 2.6 million jobs according to the Bureau of Labor Statistics. In the last two months of the year the job losses really accelerated (see chart below).
2008 Job Losses by Month. (NY Times Chart)
It is well known among economists that large job losses put stong downward pressure on home prices. As job losses continue to be high in the first quarter of 2009, expect job losses to play an increasingly large role in further reducing home prices.