Change gnome panel color

To change the colour of the fast user switching applet [and gnome panel], open the file to edit the colours using:

gedit .gtkrc-2.0

Then add these lines into the file:

style "modpanel"
{
  fg[NORMAL] = "#FFFFFF"
}
widget "*PanelWidget*" style "modpanel"
widget "*PanelApplet*" style "modpanel"
widget "*fast-user-switch-applet*" style "modpanel"

Now run this code to reload the panels:

killall gnome-panel

And you've got modded panels. Just replace the 3rd line with whatever colour you'd like the text to be.
Hope this helps!

Source: http://ubuntuforums.org/showthread.php?t=47776