Your Outlook 2000 .pst file(s) may have been converted
automatically to Outlook 2003 format when you installed Office
2003. Follow the instructions at
http://support.microsoft.com/kb/839109/en-us "You receive a '.pst
is not compatible' error message when you open an Outlook 2003
..pst file in Outlook 2002, in Outlook 2000, or in Outlook 98" to
convert the Outlook 2003 .pst file(s) back to the older format
before uninstalling Outlook 2003.
Yes, you can remove Outlook 2003 without uninstalling the rest of
Office 2003 by clicking on Start | Control Panel | Add or Remove
Programs | Microsoft Office 2003 | Change | Add or Remove Features.