Are you annoyed because Outlook 2003 doesn't remember which calendars you had selected?
Public Calendar Choice for Outlook is a freeware tool for Outlook 2003 and Outlook 2007 that will keep your preferred calendars selected.
Public Calendar Choice for Outlook
With Public Calendar, you won't need to deselect the default calendar and select the desired calendar(s).
Published February 9, 2007. Last updated on June 17, 2013.