Generic Windows Tweaks

[b]Minimize Outlook to Windows System Tray[/b]

Open regedit and navigate to you Office location. You may have to change to "10.0" folder path if you are running a different version of Outlook but the rest should be the same.
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Preferences

Add a new DWORD value named "MinToTray" and give it a value of 1.