palm muting

You place your right palm over the strings you're playing, which gives them a muted sound while you're playing them. I made a little audio to demonstrate the contrast between palm muting and normal playing:

http://www.progressions.org/music/palmmuting.mp3

Hope that helps!
Jeff

The term is a little misleading, as it's the edge of your palm, not the whole palm, that makes contact with the strings. Placing the edge of your palm on the strings (near the bridge), partially mutes them and leaves your fingers free to flatpick or fingerpick.

The way I do it is Hold your pick normally and extend the bottom 3 fingers out straight. Lay that fat part on the far back edge of the bridge with your hand held perpendicular to the body of the guitar (pick pointing up/bottom 3 fingers pointing away from you). The fat part of your hand should should be barely touching the back ends of the strings. Keeping the edge of your hand in contact with the bridge/string ends rotate your hand down towards the strings. You can experiment with different amounts of pressure on the strings to get a full mute or just a little deading. I do the partial mute when I have a slap-back delay on so that it's a more pronounced/defined delay.

If you have heavier strings on the bass and are playing on the bridge pickup you can simulate a baritone "tic-tac" bass thing.

It takes a little fiddling to get the different degrees of muting but it gives you several voices.

silvertone

Whem palm muting you can usually only pick three strings, first three on a up strum last three on a down strum, so don't try to strum them all you'll only get frustrated.

Thanks for the quick responses

@ progressions: Nice demo. Thanks for that.

@ silverone: Great description and thanks for the pics.

Just about to embark upon palm muting so this couldn't have come at a better time. Thanks to all. 8)