Realtor.com has launched a free downloadable application for mobile devices. The new application will allow users to search home listings from cell phones, depending on their location. The free feature is the first of its kind in the online real estate world, according to Realtor.com, said to be the nation’s most comprehensive online real estate listings site. The application is likely to change how consumers and realtors interact because it will give users a sneak peek into homes on the market with no help from realtors.