Office 2003 sp3 slipstreaming installation

Extract the service pack with:
c:\temp\Office2003Sp3-kb923618-fullfile-enu.exe /t:c:\temp\OfficeXpSp3 /c
Slipstrem it to administrative installation:
C:\>msiexec /p c:\temp\OfficeXpSp3\mainsp3.msp /a \\rcm-ts01\office2003\pro11.msi SHORTFILENAMES=TRUE /qb
C:\>msiexec /p c:\temp\OfficeXpSp3\owc11sp3.msp /a \\rcm-ts01\office2003\owc11.msi SHORTFILENAMES=TRUE /qb