BLM Info: Land for Sale? Sound Money Tips » Tip On Getting Free Land. Zillow.com - Your Edge in Real Estate. 10 questions I asked when choosing an Agent. Real Estate on the Web. In the NY Metro area I have found zillow is quite often wildly inaccurate. If you want the lowdown on a property, then [propertyshark.com] is an excellent resource as it ties in much of the public records information about a home into one easy to use site (including deeds, mortgages, liens, violations and Certificates of Occupancy).
In Nassau County (Long Island) neither zillow nor propertyshark are very accurate as the public records system out here is so ridiculously slow as to make the information useless. A word about "living-breathing" Realtors: I've been helping folks with mortgages for seventeen years. The advice I've always given to clients is: -locate your neighborhood (this LH article is an excellent example of how to do that effectively) -locate an experienced Realtor in that neighborhood.
-I know how fantastic a resource is the 'net. Lastly, to LBSurfer, referencing your comment above: be careful of MLSLI.com. The age-old "oops!