There are 3 different types of properties that I THINK you are inquiring about; Properties that are for sale but the people are behind in their mortgages, properties that banks have foreclosed on and took position of and properties that have liens due to back county, state or federal taxes (or a combination), or have been seized and will be sold at auction.
Many times properties that are behind in mortgage, taxes, or other liens are listed for sale with a broker. However, not all are, especially if people are still living there and there is a nasty divorce going on, multiple liens, etc.
County, State and Federal foreclosure sales are announced in the local Law Journals and many times are not listed. Properties that have been foreclosed on by banks or a third-party will many times be listed in the local ML system. You have to be careful with tax foreclosure sales because they many times they are sold with a Quit-Claim deed and you assume the title as is. This also limits the buyers to only cash buyers. Bank foreclosures will usually clear up the title and provide you with a referee's deed.
In purchasing property like this, your closing costs are more than a regular "arms-length" transaction because YOU may have to pay for the update of the Abstract of Title, Survey, Deed Transfer Tax etc.
I recommend that you contact a Real Estate Attorney who has experience with foreclosure transactions in our area and can give you the proper advice regarding the purchase of such a property.
Associate Real Estate Broker - MJ Peterson Real Estate