Propert Auction dates are posted in the newspaper, and should be posted on RealtyTrac if you are a paid subscription member. Another source of information is http://www.propertryshark.com.
Realtors typically represent the seller during lis pendence (pre foreclosure) and if the home doesn't sell at the auction and the bank takes the home back. The the home becomes a REO, or Real Estate Owned. The best price is at the auction. If you want the home and it has not been slated for auction, find the owner or agent. As with any auction, it goes to the highest bidder or the bank keeps it providing the minimum number set by the bank isn't met akin to ebay.