The majority of Realtors in the area will have a list of foreclosures that they can share with you. In addition to foreclosures and short sales, HUD also owns and sells properties. However, only HUD-registered brokers are allowed to process these transactions. The entire offer is handled online, so it takes much of the emotion out of the home buying/selling process. This works for some, for others it can feel too impersonal. I am qualified to handle these transactions; here is the webpage to search by Massachusetts county: http://hud1.towerauction.net/e12/gen_list/county_pages/MA.htm
You are welcome to contact me for more info. I was raised in Haverhill, and know the neighborhoods very well, the good and the not so good...
All of the sites mentioned are good for finding properties that are in the foreclosure process. The problem with that is most of these homeowners owe more to the bank than their property is worth. So unless their bank (and in many cases, 2 banks) are willing to do a short sale, it's usually not even worth persuing.
You are much better off waiting until the bank ends up buying the property at auction, and then places on the market. I have found that they are much more open to negotiation once they own it, especially if it sits on the market a while. Most good agents can set you up to receive an email when a bank owned property comes on the matket through the use of keywords in your search criteria.
The best way is to contact a Realtor or a title company officer. We both have list of foreclosures in our local area which we can share with our clients.
Most of the foreclosures (other than the being auctioned ones) are listed with Realtors now a day. Once you identified one, the Realtor can also help you submit an offer and walk you through all the processes including but not limited to inspections and ensure local government regulations are met. They will also advise you on whether this specific house is really as a good deal as it seems.
Use this link http://www.realtytrac.com/freesearch.asp you can search by zip code and it will give you the street name of properties. If you want more info on any of them you can contact me and I will e-mail you the full listing sheet.