You are building an app and want to convert latitude and longitude coordinates into a something the average person can understand. Here is a new, free option for you. From the OpenStreetBlock site:
OpenStreetBlock is a web service for turning a given lat/lon coordinate (e.g. 40.737813,-73.997887) into a textual description of the actual city block to which the coordinate points (e.g. “West 14th Street bet. 6th Ave. & 7th Ave”) using OpenStreetMap data.