In Outlook 2003 and 2007, the Navigation pane may contain a list of views available for the folder. If you have a large number of folders, the Current view section is usually hidden until you scroll down, but in the Calendar pane, the number of navigation calendars shown in the view is reduced. If you prefer to see more calendars or remove the clutter of extra links, you can remove the Current view list from the Navigation pane.

In Outlook 2007, go to View, Navigation Pane, Current View Pane to disable (or enable) it.
In Outlook 2003, go to View, Arrange by, Show views in Navigation pane.

The links in the section with Open Shared… and Customize current view are not removable.