I think what you're looking for is the county tax auctions. I've been to the wayne county tax auction and there are a TON of tax forclosures on the block. Just go to any county website and go to the Tresury link. The listings usually come out about a month or two before the auction. I believe wayne county's auction is in August. BEWARE!!!, do your home work. Just because a property has an address does not mean that it's the parcel with the house on it, it could be the vacant lot next to or behind it. I watched quite a few people bid redicules amounts of money on vacant lots.
You can find lists of government tax sales at http://www.taxsalelists.com - The lists are organized by county and sale date. It's in an excel format
It's a good start! Also check your local gov't sites in your area.