Windows Xp Service Pack 2 Technical Preview availbe
For those who want to test the new service pack, Microsoft is making available this preview, based on Release Candidate 1 (RC1) of the SP2.
Microsoft Windows XP Service Pack 2 (SP2) provides an enhanced security infrastructure that defends against viruses, worms, and hackers, along with increased manageability and control for IT professionals and an improved experience for users.

Changements for 273 megs are one of major update even from Microsoft.
Windows Xp Service Pack 2 Preview

Note: This technical preview is unsupported and is intended for testing purposes only. Do not use in production environments.