hmmm mabe it could be your in take. mine whistles when im driving but not when im sitting and when i take my foot off the gas it stops. that happens to mine cause my battery tie down rubed a hole in it. check that first if not that then im thinking it could possibly be the tranny. i dunno check them both im sure someone will have some in put on this

Does it happen when you sit still?

D'OH!  Reading justed owned me. 
 
OK, so its not the intake then.  It's something that only moves under acceleration.  Probably the transmission, though I cant think of anything that would stop whining even though the car is still moving... 

That's weird man.  I was going to say wheel bearing, but if it goes away only when you take your foot off the pedal, I'm stumped.

I'd say it almost has to be something with your TB.  It's really the only thing that is directly affected by the pedal.  But then it would do it at idle too..........

This flat out doesn't make sense damn it.  You're just trying to piss me off!!   If it doesn't do it when you're revving, that takes away the belts, the TB and your entire intake as a possibility.

So that leaves wheels/suspension.  But it goes away after you let go of your pedal.  So it's not your wheels or suspension, or your tranny, or anything that's rotating.

Do you have an automatic or manual.  When you take your foot off the accelerator do you push in the clutch (manual)?

if the noise changes with engine speed versus wheel speed that can help narrow it down. any vibration or just noise?

Ok, so maybe its a cv joint or something of the like.

i think dt is right. hes just trying to piss us off