Apartment Search from Walkscore
This online application has been developed by Walkscore to help people to find a walkable place to live. It helps identifying the neighbourhoods with the best mix of dwellings, services, commercial activities and amenities in the town you are going to move. Furthermore it shows the quickest way to commute to and from work, which is another basic information you need when looking for your new place. Unfortunately it works only for the US, yet… I hope we will soon get it in Europe as well.