What do I need at a house auction?

I'm trying to buy a cheap house for investment so I went to the courthouse and found listings of foreclosed houses that will be auctioned on Tuesday (Jan 06, 09). I've never done anything like this so can someone tell me what I need? Do they only accept cash? Can I take a pre-qualified statement from a broker? Can I get some type of loan that will allow me to bid for what I qualify for? Do I need some type of license? What about the down payment? I know these are allot of questions, I sent an email to a few relaters two days ago but I've yet to get an answer. They will be auctioned in Houston at the Family Law Center. I'd appreciate it if someone could give me any information thx.