Guess what I'm in the process of doing -.-
There is one caveat with this though. You are usually NOT allowed to participate in the auction if you are the previous owner or if the previous owner was a living relative. You also usually need to put 10% of the total assessed value down in cash at the auction.
There are also companies that are starting to specialize in buying homes for cash on the steps and then refinancing a loan for the home owner. Its brilliant really. Someone's $250k home gets foreclosed on. No one wants it cause its owner occupied. But these companies have already setup a relationship with the owner. They buy it for $50k, then finance a $50k loan at 15% interest. Investors win cause of the interest rate, home owner still generally sees a giant drop in mortgage payment and gets to stay in their house.