There are several auction companies ... and they're not limited by zip code. Two of the bigger ones are Hudson and Marshall and U.S. Home Auction.
You absolutely get to preview the home. You can do that by watching for the Auction Open House or by contacting an agent to get you inside.
The homes are vacant. The banks will not market a house until it's vacant (either through walkaways, cash for keys, or eviction).
Be careful with auctions. The contracts are usually written in such a way as to limit your contingencies and punish you if you do not close (for any reason).
Auctions are not for the weak. Attend a few before you buy. Get your financing approved BEFORE the auction. Visit the house with a good inspector beforehand. Know your comps too!
The thing is, a good agent can get you the same auction price with better contingency protection. But if you do it often enough, and know your markets and comps, you can occasionally find a good buy quicker than writing offers the traditional way.
Don't be afraid to work with a good agent. We get paid on auctions too ... I've helped several clients that way. Then you get the benefit of knowing what all the paperwork is really saying and, more importantly, what the disclosures mean.
Thanks for the opportunity to answer your question and compete for your business. If I can help with anything else, please feel free to contact me directly at 951-571-9229 or firstname.lastname@example.org