There are a number of sites all over the Internet that will give you information about properties just about anywhere in the US. If you type in Real Estate then the area you are looking for - a wealth of information will appear but it can be very confusing. The best place for you to start is with a good agent in the area you are interested in.
Just in case you don't already know, the process for buying real estate in the United States is very different from the way it works in the UK. First of all, the agents here are all required to be licensed by the state in which they work. They must complete a course of study as well as pass a state exam before becoming licensed to work for the public.
Secondly, most agents offer a commission to agents from other companies if they bring a buyer to purchase their listing. There is a service in most areas called the Multiple Listing Service where agents can put the information about their listings for other agents to access. You can find out just about everything that is listed from one agent instead of having to go to several companies to find out what listings they are offering.
Thirdly, agents here write a contract for you when you find the property you want to purchase. You do not have to wait several weeks and then go to a lawyer to prepare the contract for you. When you offer on a property and that offer is accepted by the Seller, you know you are going to be able to purchase it if all the contingencies you put in the contract are met. You don't have the chains like you have in the UK and there is no gazumping.
Further, real estate agents here represent their clients interests and have certain obligations to you through their duties of agency. Here is a link to the State of South Carolina Agency Relationships brochure that will explain it to you. http://www.toonpawley.com/agencydisclosure.html
Agency Law varies from State to State but the basis of the law is essentially the same.
The bottom line is that you need to find out what area of the US you are interested in and then search for an agent in that area who not only can work for you but who is skilled, knowledgeable and has a good track record. ( If you don't know where to start, I will be glad help you find one through my network of top agents if you'd like to contact me directly.)
I hope that helps you. Good luck in your search.
Julie Toon Pawley, ABR, CCIM, CRS, e-PRO
Real Estate Broker
Hilton Head Island, SC