Majority of businesses still avoiding XP SP2
According to this article over at BetaNews, the vast majority of businesses that use Windows XP haven't upgraded to Service Pack 2. The article is based on a study of 251 North American companies, less than a quarter of which are running the latest service pack. Microsoft has actually set an April 12 deadline for Windows Update SP2 upgrades. After April 12, "Windows XP SP2 will be delivered to all Windows XP and Windows XP Service Pack 1 systems."
Windows XP users can currently use a Microsoft-supplied script to block the installation of Service Pack 2. The script modifies a registry value that Windows Update checks before installing Service Pack 2. However, after April 12, Windows Update will ignore the registry value, leaving users with no way to avoid SP2 without disabling Windows XP's automatic updates.