If you are talking about pre-foreclosure (short sale), generally these are handled by a realtor. Be prepared to wait while the bank considers offers and decides what it wants to do.
Generally, all of these sales are "as is" which means that the usual protections afforded a buyer do not exist--such as a home inspection which we recommend on all purchases, with the attendant repairs prio to purchase to protect the buyer.
Good luck, and happy househunting!!
My best suggestion to you is use a Realtor who is experienced in REOs, and can walk you through the process. Look at the area you want to buy in and see which brokerage companies are selling there.
Remember, you may be working with a Reator for quite a while, so make sure the person is looking after your best interests and the two of you are compatible.