Create a new PST file (in 97-2002 format) using the File menu > New >
Outlook Data File command. Copy your Calendar folder into the new Personal
Folders, close the folders, exit Outlook. Bring that file over to the OL2000
machine, open it using the File menu > Open > Outlook Data File (or Personal
Folders - I forget the exact command in OL2000). Edit the data and close the
file. You can then bring it back to the OL2003 machine, open it and copy the
data back in