Unless you've been missing the TV lately, you'll have seen the "Crazy Frog Dance Remix" mobile phone ringtone advertisment. Seeing this reminded me of the original sound i'd heard ages ago, so I set about finding out a little bit about it.
It seems that Erik Wernquist is the creator of the animation:
http://www.newtek-europe.com/uk/community/lightwave/wernquist/1.html
And the sound comes from Daniel Malmedahl , and I originall heard it here:
http://www.funnyjunk.com/pages/insanity_test.htm
or here:
http://www.jokaroo.com/ecards/funny/racecarnoises.htm
Anyway, I thought that was enough research, enjoy ;-)