Desktop/Whiteboards/VolumeApplet

Problem
The volume control that lives in GNOME panel currently has a number of problems:
 * It can be removed by the user
 * It can be added multiple times
 * It shows up whether or not there is actually an output device
 * It can be moved anywhere on any of the GNOME panels

Relevant Art
The volume control on Windows and OS X cannot be addeded multiple times, removed, moved. On Vista it only shows up when an output device is available. For example, when I plug my headphones or speakers in it shows up immediately.

Discussion
Volume control should be converted to a notification area applet that should only be displayed if there is an output device connected.