From Microsoft
"As you know, Microsoft recently released Windows XP Service Pack 2 (SP2) to manufacturing on Friday, August 6, 2004. You may also know that Microsoft will deliver Windows XP SP2 through the Automatic Update delivery mechanism in Windows as a critical update. This process began on Tuesday, August 10.
Since some of our customers, such as your organization, utilize Automatic Update for a collection of your PC"s, and since your organization may not yet be prepared to deploy Windows XP SP2 onto those machines, we recently made available a mechanism for temporarily blocking the download of Windows XP SP2 to those machines using Automatic Update. Last week, we received feedback from our corporate customers that they would like more time to put this temporary blocking mechanism into place. Based on that feedback, we have altered the delivery schedule of Windows XP SP2. The machines in your organization using Automatic Update will not receive Windows XP SP2 until Wednesday, August 25 – at the earliest – as long as those machines are running Windows XP Professional Edition.
Here is a summary of the altered delivery schedule for Windows XP SP2:
Release to MSDN subscription site (CD ISO image)
Release to Windows Update for interactive user installations