I know some measures must exist, but I have no idea what the programs are, what organizations are involved, or how effective they are.
NASA doesn't have its own asteroid tracking program. They are rather coordinating activities and provide funding for asteroid research and discovery programs.
The most successful dedicated asteroid discovery programs at the moment are Pan-STARRS (http://pan-starrs.ifa.hawaii.edu/public/) and the Catalina Sky Survey (http://www.lpl.arizona.edu/css/); see http://neo.jpl.nasa.gov/stats/ for some discovery statistics. Both these programs, as well as many others, run telescope that survey the night sky for yet unknown asteroids. On average, both programs together find 4 new near-Earth asteroids (and many others) per night.