Realty Trac reports that for the third quarter of 2007 " ... 30 percent increase from the previous quarter and an increase of nearly 100 percent from the third quarter of 2006."
Where are the foreclosures concentrated? For the third quarter of 2007, Nevada was number 1, followed by California and Florida. The top ten is completed by Michigan, Ohio, Colorado, Arizona, Georgia, Indiana and Texas.
There is a lot of data plus a chart on the Realty Trac website. You can read more: Realty Trac