Wow
A very well made Flash!
And its very crazy that I ran across this. I've had the idea mulling in my mead for a bit now of doing this exact thing with the Protomen songs. (I should rage at you for getting to it first hehe ;) )
I like how you made the mouths actually be part of the sprite. I hate when people use game sprites and just use vectoring for the mouth to move (especially on "O" sounds)
I may try my hand at it myself still, but keep your work coming.