Well the LimeWire mp3 player is very basic, and doesn't have one.

You can use the the volume control on your speakers if you have one or use the volume control from your sound card.

You can also use an external program outside of limewire that has a volume control if you have one.

You can change the settings in LW tools>options>player ---- uncheck the box. Click apply then okay. You will also need to close then restart LW for the changes to take effect. This will use your systems default mp3 player, which probably has a volume control on it.

Best of luck