Listening for changing values

Hey…
I’m trying to do something in AS3 and failing!!!
I have an Instance of the FLVPlayer on the stage called ‘video’
and when its buffering …

video.buffering = true;

I want to display a movie clip

buffering_mc.visible = true;

does anyone know how i can use addEventListener statement to listen for the value of video.buffering changing??
Or should i loop an ‘If else’ statement???

Any help would be awesome!! Thanks