flight tracking mashups available online.Labnol described about a brilliant mashup that displays movement of incoming and outgoing flights from Amsterdam Airport called Casper (link ad suported)which can be configured for some select airports as well.
Below are some more Live Flight Tracking google map mashups. (all links are ad suported)
Gmaps Flight Tracker is a simple mashup which provides inbound flight information on several of the most popular airports in the U.S. including NY, Atlanta, Boston, etc. It works pretty well though it appears to only display flights relatively close to the arrival airport.
Air Traffic Zurich is mashup which shows on-line real-time air traffic over Switzerland and some more countries in Europe.
Flightradar24 which shows live aircraft traffic in the airspace above whole of Europe. Howver only aircrafts equipped with an ADS-B transponder are visible on the map.
Radarvirtuel covers contries like France, UK, Ireland, Spain, Portugal, Finland, Cyprus, USA, Canada and Brazil.
Well, if you are interested in finding the real time flight status, any flight across and city in the world, the below link could come handy..
FlightStats
Friends if you come across any more online real time flight tracker, please do share via comments below.