level of difficulty:
Palm muting is a common technique in rock guitar playing. Resting the side of your palm on the guitar bridge gives a percussive quality to distorted chords. The trick is using just the right amount of palm pressure: too much and you wont get any sound, too little and you will loose the chunkiness.
Have a look at this video from Gary Schutt . Gary has a degree in songwriting from the Berklee College of Music and has written over 150 songs, has 5 CD's, and 1 DVD currently available.