Yesterday, while searching with a couple of [city+real estate] keyphrases I noticed two new fields at the top of the organic results: Location and Listing Type (here is quick example San Francisco Real Estate). Location by default already has your city name and listing type provides drop-down list of the following choices: all, for rent, for sale and room to rent.

When choosing for rent, Google shows you rental listings with their location on Google Maps. For Sale - takes you to Google Base and shows all the properties for sale in earlier specified area (of course those are not all the properties, but just the available in Google Base). Room for rent works exactly the same way as For Rent option - with the maps etc.

Very cool stuff. Every property listing links directly to the original website to pages where the actual listings published, so owners get the credit.

To find out more about Google Base and how to submit and manage your items and feeds check out Google Base Help. Their official blog might be useful too.