These need very little introduction other than a link and a visit.

Most display flights in realtime. A few are delayed for “security” reasons.

Check them out and explore what’s available.  Some have chat rooms and forums where you’ll find radarspotters, both newbies and the more experienced.

Aircraft Tracking sites usually display all aircraft.  Flight Tracking typically allow a search for a specific flight.

Aircraft Tracking Websites

Atlas
www.flightglobal.com/atlas
Casper
http://casperflights.com/
FlightRadar24
www.flightradar24.com
PlaneFinder
www.planefinder.net
RadarVirtuel
www.radarvirtuel.com

Flight Tracking Websites

Aeroseek
www.aeroseek.com/webtrax/
Flightaware
http://flightaware.com
FlightExplorer
www.flightexplorer.com
Flightstats
www.flightstats.com
Flightview
www.flightview.com
Flightwise
www.flightwise.com
FlyteComm
www.flytecomm.com