rrifen,
Go to View > Current View > By Category
You will see the section titled:
Categories: Holiday and all the holidays listed below that. If you do not see the actuall holidays listed, click on the plus-sign to the left of the word 'Categories'.
Click on the first holiday listed to highlight it and then scroll down to the end of the list. Hold down the Shift key and click on the last holiday entry. All the holidays should now be highlighted. Hit the Delete key on your keyboard.
Go to View > Current View > Day/Week/Month to restore your normal view.
Now you can go to Tools > Options > Calendar Options > Add Holidays to put the holidays back in.
I'm going to assume you "accidentally" hit the ADD holidays twice because the holidays weren't being listed for the year 2003.
In order to see the holidays for the years 2003 - 2007, you have to install the "Add-in" that is available here:
Outlook 2000 Add-in: Holiday Updates