For any specific search: schools, zip codes, etc, agents can send you listings direct from MLS (FMLS and GAMLS in Georgia). They can also set up an alert that will send you new listings AS SOON AS THEY HIT THE MLS. You (along with a whole bunch of real estate agents) will get a first look at properties that come on the market in your target area. This is the way to go for serious buyers.
Also, you can refine this search by specifying a price range, bedrooms, basement etc. Pretty much any specific physical feature.
Good luck with your house hunting.