Works in XP
I just thought - maybe I have misunderstood the question - I supposed the OP wanted to know how to minimize Task Manager to the system tray / Notification Area - but he might be asking how to put a launcher there - personally I just have a shortcut to Taskmgr.exe in my Startup folder, and choose "start minimized" and since I have checked "Hide When Minimized" it just sits there in the tray showing the CPU usage bar graph and I double click it when I want to use it for anything else.