Emerge Desktop is a replacement windows "shell" (the desktop environment normally provided by Windows Explorer) for Windows 2000 and above. In order to replace Windows Explorer as a shell, it provides a system tray (the area that collects the icons collected at the lower right corner in Explorer), called emergeTray. It will also provide access to the users programs (normally accessed with the windows "start" button) via a right-click on the desktop, via emergeCore.
FilerFrog makes it easier to manipulate files in windows explorer.
It integrates with windows explorer as a shell extension so it can provide you with tools to perform your every day file manipulation actions easily and efficiently.
FilerFrog was formerly a commercial product and it's now a free Open Source software.