I've heard this noise coming from the speakers on my machine. It lasts about 5-6 seconds then stops.
I heard it coming from a radio at university after a listening exercise. I've also heard it a few times from a portable TV that is kept next to my machine.
I showed the movie to my sister when she called, she's also had the noise from her PC speakers and has no idea what it is.
I managed to catch it one day when I had my camera switched on.
www.hotlinkpro.com/fuckityfuck.avi 570KB
Does anyone have any idea?