Trulia is a good way, there are several subscription services, and lately I've noticed that the banks themselves have reasonably up to date location services. (Find Bank of America Properties). You should know though, that the majority of the foreclosures are in the secondary cities, like Worcester, Lowell, Fall River, etc. There are not very many left in the suburbs.
Here is a great site to find what you would like:
If of course you still need the information
Serving Blackstone Valley and Worcester Counties
877-266-9747 ext 281
I suggest resubmitting your question under Massachusetts. Every State has different laws, but you are able to search for foreclosures on Trulia. Simply search for homes as usual and on the left side of the screen there is a check box for foreclosures.
I do suggest working with a Buyers Agent with some experience in foreclosures. An please remember, they may take more than 3 months to close. Banks operate on their own time schedule.