I just noticed this at the bank the other day and was wondering if it's something I should be worried about...

Whenever I'm idling w/my foot off the clutch, I can hear this speaking/vibrating noise coming from under the hood. When I press down on the clutch, it goes away... Does anyone know what this could be? The car runs perfectly fine right now.

 

It could be your bels or alternator messed up thats what happened to me i had to replace the tensioner both belts and the alternator they wer all messed up

 

hmm clutch throw-out bearing?

If it's really tied to the clutch then it's your TO bearing. You should be able to hear the noise slowly fade as you slowly apply pressure on the pedal and so apply pressure on the bearing.

 

i would second the throw out bearing.