A notice of trustee sale means the home will foreclose, unless the owner catches up on the missed payments, gets a loan modification, or short sales it.
There are several possibilities:
1. It could be available for sale, likely a short sale, right now. A local realtor can answer that question for you. If it is, you can make an offer on it, and it will likely require bank approval in addition to the seller's acceptance.
2. It may end up going to auction. Foreclosure auctions are public, you could bid on it there. However, you will need to pay cash for the home, and will have no inspections or warranties.
3. Likely if it goes to foreclosure auction, the bank gets it back. Then they will list it for sale as a bank owned/REO home, with a local realtor. Then, you can buy it without the legendery problems many short sales are.
Neither the designated trustee nor the mortgage holder can sell you the home - http://ForeclosureProcess.net