Italian proofing tools (dictionary, thesaurus, etc.) are included
with the Croatian, German, Italian, and Slovenian language
versions of Word 2003.
If you have one of these language versions of Word 2003, then you
can add the Italian proofing tools feature to your existing
installation by clicking on Start | Control Panel | Add/Remove
Programs | Microsoft Word 2003 | Change | Add/Remove Features.
If you do not have one of these language versions of Word 2003,
then you can purchase the Proofing Tools CD for Office 2003, and
install the Italian proofing tools from the Proofing Tools CD.
See
http://www.microsoft.com/office/editions/prodinfo/language/proofingtools.mspx
for more information.