MoonTool for Windows calculates the phase of the Moon at
either the current time or at any user-specified time and
displays a picture of the Moon at the correct phase, either as
a system tray icon or in an open window.
When the MoonTool window is open, it displays comprehensive information about the Moon. When MoonTool is minimised, it becomes an icon in the system tray which shows the current phase of the Moon; selecting its icon restores the original display. If you'd like a permanent Moon phase display in the system tray, add a shortcut to MoonTool to your StartUp folder with the Run property set to Minimized.
MoonTool is a 32-bit Windows application which runs on Windows 95/Windows NT 4.0 and above.