The others have the best answer - a realtor would be most efficient. Banks usually list their REOs on their web sites as well but you'll have to check each bank. The bank I work for, fortunately for our customers, has no REOs in this area.
I agree with Scott. Contact an realtor in your area who has experience with selling and listing bank owned propeties, REOs. They can put on their list so that when foreclosures first come on the market you'll get an email alert.
The bets source of foreclsoures is a buyer broker who is experienced in working with bank owned homes. The first step is searching for homes that currently on the market but the best deals are teh ones that just come on the market and getting their first.
Please see my blog for tips and advice on buying bank owned homes
You can search the local Tax Records by name of bank, closing dates, zipcodes, any criteria for addresses of REO properties, you need a Realtor to assist you to make it simpler. They have MLS systems that usually post all the REO properties in a given area, or zipcode.
Bank owned properties are usually listed on the MLS (Multiple Listing System) the same as regular resales. Banks don't usually sell properties. They hire a real estate firm to sell them. Any good website that lists properties in your area should include foreclosure properties.
Long & Foster Real Estate, Inc
Lehigh Valley Office, PA