Windows Mobile has independent controls for phone volume and system volume. On the title bar, the speaker icon gives you quick access to both.

Tap it and you get separate sliders for each, plus the option to switch either or both to vibrate or to turn off the sound. To toggle between the phone and system sliders, simply tab the slider you want.

If you're listening to content with Windows Media Player, you can also control the playback volume within the software. In the media player, tapping the speaker icon lets you toggle between mute and on. The + and - buttons are how you adjust the volume up and down.

When using your earbuds with a device, such as the Verizon VX6800, you may have an additional option. The buds that come with this and some other Verizon devices have their own independent volume control on the cable that plugs into the device. Incidentally, the button on the Verizon earbuds lets you answer the phone if it rings while you're listening.