Removing all mounted volumes from desktop

If you go to gconf-editor, under

apps->nautilus->desktop->volumes_visible

and switch it to false, you will get rid of all your mounted volume icons on desktop

Removing only fixed drives

But, if you have users who would like to see there DVD-ROM's and USB keys mounted, you have a problem. This cannot be changed by GNOME.

Fortunately for us, GNOME uses HAL to detect which drives it wants to display.

If you enter

sudo vim /usr/share/hal/fdi/policy/10osvendor/debian-storage-policy-fixed-drives.fdi* 

and add following content:

<?xml version="1.0" encoding="UTF-8"?> <!-- -*- SGML -*- -->

<deviceinfo version="0.2">
<device>
  <match key="@block.storage_device:storage.hotpluggable" bool="false">
    <match key="@block.storage_device:storage.removable" bool="false">
      <merge key="volume.ignore" type="bool">true</merge>
    </match>
  </match>
</device>
</deviceinfo>

Restart the HAL, by issuing:

/etc/init.d/hal restart

and login and logout of your gnome. That's it. No more pesky drives on your desktop.
This concept can obviously be tuned for your purpose.