After a quick research on the topic I found these 3 – RBtray, Trayconizer, HideIt, Below is a very quick review on each
1. Minimize any Windows program to tray with RBTray
If you want to stick to open source (GPL) software a tiny free software proggie that does the trick is RBTray current latest RBtray is 4.3 release is download mirror is here.
To use RBTray you don't need to do anything, once program is unarchived from archive, once launched there will be no system application that it is running, but you can go to any minimized program (not in tray) and by clicking with right mouse button on minimize button you will the app minimize to tray.
Here is how RBTray works (taken from archive README file):
Extract the 32-bit or 64-bit binaries (depending on your OS) to a
C:Program FilesRBTray. Double click RBTray.exe to start it. If you want it
to automatically start after you reboot, create a shortcut to RBTray.exe in
your Start menu's Startup group.
Right click on any program's minimize button to minimize it to the tray. To
restore, single-click the program's icon in the tray.
Right click on any tray icon created by RBTray and click Exit RBTray in the
popup menu. Or run RBTray.exe with the –exit parameter.
Trayconizer is the other tray minizer tool you might want to check out, Windows tray minize application a download mirror of Trayconizer is here. As of time of writing this post (current) latest Trayconizer version is 1.1.1.
Trayconizer allows you to minimize virtually any application to the system tray rather than having it take up valuable space in your taskbar. The screen shot to the left shows Trayconizer minimizing Notepad to the system tray. Trayconizer is definitely the tool of choice of system administrators who need to keep minimized windows program to system tray each time on boot as it can be easily run from command line.
Using Trayconizer is simple. To start Trayconizer on Notepad, you would execute: C:PathToTrayconizer.exe C:WindowsNotepad.exe.
You can create a shortcut in your Startup group to execute Trayconizer on a program that you use frequently but want to keep tucked out of the way in the system tray when you're not using it. There is even an option for starting the application initially in the minimized state.
Trayconizer will automatically shut itself down when you close the program you are Trayconizing. Additionally, multiple Trayconized programs are handled by a single instance of Trayconizer to avoid wasting system resources.
Another good tool useful in hiding (minimizing) Windows programs which are lacking the minimize option embedded built-in is Windows HideIT.
Hideit official download website is here, note that with Hideit, Its pretty confusing to find where to download in (so to download look in the right upper corner for a download button) HideIT Download Mirror is here.
Hideit should be able to minimize any Application to sysytem tray, while Rbtray fails ith some. Both RBtray and Windows
HIdeIT will popup with a blue down-arrow on Tray icon once launched and you can show / hide minimized applications from there.
All RbTray, Trayconizer and HideIt tray minimizers should work on virtually all NT 4.0 Windows XP / 2000 / Vista / 7 / 8 though I haven't tested on all of 'em yet. If you happen to find it working on Win NT 4.0 / 8 etc., please drop a comment.