A LifeHacker story currently doing well on Digg highlights this free service, which will track any US flight for you in Google, live:
Closer inspection reveals that the information is in fact provided by fboweb.com, previously featured on Ogle Earth for their airport tracking network links. A trip to fboweb.com led me to their Quick Track, a free service very much like the one dugg above, only that now, you not only get your flight, you also get every nearby flight, live.
Nervous fliers are probably grateful this isn’t yet available on the in-flight entertainment systems.