What's your goal? Different goals lead to different path.
Whatever your goal, detailed preparation is key. You need to know the condition of the house, hence its value before hand. No matter which type of auction you go to, the action is vary fast. They may wait for you for 30 seconds, or even a minute, but not longer. So keeping a cool head is important.
If you want the foreclosure auction, then you need to look for local legal newspaper, which published the court announcements. Call your county government, they should point you to the right newpaper.
If you want to check out REO auctions, look for REDC, William William.
Both auctions have good deals, if you know what you're looking for. However, it the part about "know what to look for" is the hardest to grasp.
Hope this helps. Good luck.