The Zip Code Guy has a zip code database that gives you a list of US states, counties, zip codes, abbreviations, etc. It pretty useful for real estate research or marketing. You can get it for free by posting about it (like what we are doing) or paying $25 for it.
Search Engine Land has a story on how real estate agent Teresa Boardman is using new techniques to market herself on the web. She uses blogging and social media through here St. Paul Real Estate Blog. More than just a writer on her own site, Teresa writes for other sites and is on Flickr, Facebook, etc.
Her Internet success is obvious - she gets most of her leads online. Read more about the topics she writes about, how she uses social media, and how she optimizes her site for search engines.