Here is a great site to optimise XP boot times:
Hacking Windows XP: Speed Up Your Boot - OS, Software & Networking by ExtremeTech
It details the following tweaks:
-Working with the BIOS
-Changing the Boot Order of Your Drives
-Using the Quick Boot Feature of the BIOS
-Modifying the Operating System Boot
-Disabling the System Boot Screen
-Modifying an Existing boot.ini File
-Disabling Unneeded Hardware Devices
-What Hardware Devices Should I Disable?
-Removing Extra Fonts for Speed
-Disabling Unneeded Services
-Bare-Bones System Service Setup
-Recommended Service Setup
-Optimizing the Location of the Boot Files
-Using Other Shareware Boot Defrag Programs
-Boot Time Defrag with O&O Defrag
-Summary