They are typically put in the local papers. Also banker&tradesman offers a list of notices and foreclosures. Once you are aware of the attorney and or auction company you will want to stay in contact with them, as many auctions are postponed and cancelled.
You can check woth the county courthouse or registry of deeds where foreclsoures are filed or with publication like the registry review that lists auctions. You can check the house if vacant to see if it is posted or should watch the local paper each day for when teh legal notice is posted,