If you want to buy within a fairly short period of time, you should enlist the help of a local professional. While the internet offers multiple websites and a plethera of information, it can only provide so much. A realtor will go above and beyond the MLS search and actively seek information from other sources and collegues to find what their buyer is looking for.
You didn't specify what your intentions are. It would probably be in your best interest to buy a site with an existing home. You should then qualify for the federal tax credit.