You can use the registry to minimize Outlook 2002 to the system tray by performing the following steps:
Start the registry editor (regedit.exe).
Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Preferences.
From the Edit menu, select New, DWORD value.
Enter a name of MinToTray.
Double-click the new value, and set it to 1.
After you perform these steps, Outlook will reside in the system tray.