My clutch pedal starting vibrating the other day. The only two things I can think it would be is the throw-out bearing, or the clutch and pressure plate? Does anyone else have other suggestions??

 

Is the clutch chattering when you release the pedal? Its probably the flywheel or clutch disk then...
or is does it vibrate when push the pedal down? might be the release bearing, never really known them to cause any vibrations tho...usually they are noisy when the clutch is engaged - have someone push the pedal down with engine running and the car in neutral(any gear will work just a safety precaution) and give a listen, dont know what car you have but 020 trannys have the release bearing is in the end housing - a long screw driver makes a good microphone, put the handle to your ear and move the tip to different locations to pick any internal noises