Capture Fox can record all your activity inside a Firefox window or
even the entire desktop screen and will save it as a video file. The
program can also capture audio from your microphone.
You can capture your screen and record your sound to make videos (tutorials, e-lessons, etc.)
Source : http://www.labnol.org/software/make-screencast-videos-in-firefox-capture-fox/4744/
Je part tester 
Mince : Capture Fox is not available for MacOSX.
Snif Snif Faut que je reboot :/
C’est tellement génial que l’on se demande pourquoi ils ont pas fait ça plus tôt !