Ask an American

http://www.realtor.com is the best place to locate properties currently for sale.
http://www.zillow.com is a good site with some for sale by owner listings and property history details.

I have not found a reliable site for auctions or foreclosures, the best thing I can recommend is find someone in the area you want to invest that is capable of generating these types of leads. The local newspapers are the best resource for this, so sometimes their websites will list these. By law the lenders are required to give public notice, they usually do this via local newspapers. But I dont know of a one stop shop website.

The other thing to do is once you have a property that you want more information on, google search for the county assessor website and look for the property in their database if they offer an online data base search, or call the county assessors office to ask questions about the property.

-Find out if their are back taxes owed
-Find out if there is a lien on the property
-Find out if the building is up to code
-Find out what the property tax is per year

Then talk to your team about your findings and ask them questions about how they will affect you.

I dont know enough about Atlanta to make a recommendation on that market. Just FYI make sure you have insurance that covers flood, hurricane and tornado damage. That part of the country is known for severe weather.