Now, the default icon is in my opinion too heavy, and thus the developer made his own. To install, download the icons, extract and find the two icons named ClassicOff.tiff and ClassicOn.tiff. Now, locate the original ClassicSpy.menu and control-click it. Select 'Show Package Contents' and navigate through Contents and Resources. Replace the original icons with the one you just downloaded. Drag ClassicSpy.menu to your menubar and you're finished.