I just use county public records. All distressed properties are recorded with the county and information is (around here) freely available on the county clerk and recorder's website. If you don't have access, call up a Realtor and make them look for you.

Pretty much any commercial site (zillow, etc) will not be up to date or particularly accurate.

:edit: There is also a wide misconception that the only way to get a good deal is to buy a foreclosure house, or that foreclosures are deeply discounted from market value. Truth is, they are listed at market value in most cases, and are just horribly maintained, thus the price difference vs. a normal home. I dunno, in MI, it could be that every other house on the market is either distressed or bank owned :hsugh: