Fortunately for the investor (and unfortunately for the homeowners), there are thousands and thousands of properties that are available in these categories. At RealtyTrac.com, they provide an outstanding service which allows you to search by city or zip code, and find all the available properties broken down by the various categories (pre-foreclosures, auctions, etc.). Then for every property, it lists the address and the number of bedrooms and bathrooms, and when you click on the property you are interested in, it shows square footage, lot size, year built, a map showing where the property is, history of notices, estimated property value range, estimated property market value, and much, much more.
One of the nice features of this website is that it can give you an idea of how foreclosures are trending across the country and from city to city. For example, even though Los Angeles is a far bigger city than San Diego, San Diego has more bank owned properties for sale than LA. Chicago has 13,529 pre-foreclosure properties for sale whereas Houston has only 3. However, Houston has many more bank owned properties (5,513) than Chicago (4,164) (Maybe Texas is much more strict on how long a property can stay in pre-foreclosure?). Boston's auctions and bank owned properties were extremely low compared to the other major cities.
The following list should give you a good idea of the number of foreclosures across the United States.
City: Pre-Foreclosure/Auction/Bank Owned
San Diego: 1,709/339/1,174 Los Angeles: 2,494/442/1,107 Houston: 3/1,933/5,513 Memphis: 289/2,007/3,540 Miami: 6,316/1,804/2,313 Boston: 566/64/171 Chicago: 13,529/4,633/4,164