I just discovered a great website called www.housingmaps.com. What it does is intefrates craigs list for sale, for rent listings onto the map and you can even search it by price range. Check it out very interesting.
Thestory I heard was that a programmer that worked for PIXAR studios (the anamaters for Toy Story and such) had taken the Google Earth platform and crossed it with Craigslist and he called it www.housingmaps.com. It was the first "smash up" that google saw. Google was so impressed that they hired the programmer away from Pixar and now apply this "smash up" programming to everything from census data to chat sites.
For me, the housing maps becomes especially useful when I am seeking rental ads for specific neighborhoods and saves me the time of going through them all. You just have to know where a "no specific address" ad is mapped to. And one other tip, if you can’t figure it out.. the colors indicate if the ad has pictures embedded in the Craigslist ad or not. Double clicking on a bubble will bring up the actual Craigs List ad. Have fun…