Although Windows Update still does not show SP3, I am providing some guides:
A guide for the installation process
Installing Windows XP Service Pack 3 (SP3
A guide to start XP by using a minimal set of drivers and startup programs
How to configure Windows XP to start in a "clean boot" state
A guide to create a Windows Xp and SP3 CD
Slipstreamed Windows XP CD Using SP3 Final
A guide for the installation process
Installing Windows XP Service Pack 3 (SP3
A guide to start XP by using a minimal set of drivers and startup programs
How to configure Windows XP to start in a "clean boot" state
A guide to create a Windows Xp and SP3 CD
Slipstreamed Windows XP CD Using SP3 Final