Outlook 2003 is leaky on my Dell laptop. The icon in the taskbar.

[Guest]

When I close Outlook 2003, the icon in the right side taskbar does not always
close. This uses up memory (but no CPU cycles) and is very annoying.

 

[Brian Tillman]

When I close Outlook 2003, the icon in the right side taskbar does
not always close. This uses up memory (but no CPU cycles) and is
very annoying.

If the icon remains in the notification area, then Outlook is not closed.
It's not "leaky". Something is keeping Outlook open. See
http://www.slipstick.com/problems/close.htm for some ideas.