Office 2003 Introduction
Got a DVD Writer? You'll need it if you want to bundle Office 2003 with Windows XP, due to its large size. If not, you could use a 2nd CD for Office 2003, and instruct the batch file on the Windows CD to ask you to insert the 2nd CD and then run the Office 2003 installation. You can follow this guide or this guide on the MSFN Forums for the how-to.
Alternatively, you could SFX archive all the Office 2003 files with WinRAR and hopefully it will fit on your Windows XP CD. (I managed to get Office 2003 CD1 compressed to 259 MB using WinRAR SFX with Solid Archive selected)
This guide will show you how to run a silent unattended installation of Office 2003. The Simple method will just run a silent install from an existing Office 2003 CD, and installs the full default components. The Advanced method will show you how to fully customize your installation options (you even get to have control over what shortcuts to install, and whether or not to install that annoying Office Assistant!)
Office 2003 Slipstreaming | Office 2003 Simple | Office 2003 Advanced