Not to take anything away from FlightAware, but I found a site that tracks traffic around the NY airports. The page updates about every 5 seconds, so it’s very much like watching them in real time like on a controller’s scope. You can do a replay based on earlier dates and times (check out the skies over new york at 5:00 on a Friday afternoon). You can center the map on TEB, LGA, JFK and EWR. You can zoom in or out to 5, 10, 20, 40, 80 miles. You can change the speed from normal up to 10X.
Check it out at: http://aviationdevelopmentcouncil.org/F_Tracking.html