Here’s the calendar for XP SP2′s rollout:

8/6 Release to manufacturing
8/9 Release to Microsoft Download Center (network installation package)
8/9 Release to MSDN subscription site (CD ISO image)
8/10 Release to Automatic Updates (for machines running pre-release versions of Windows XP Service Pack 2 only)
8/16 Release to Automatic Updates (for machines NOT running pre-releases versions of Windows XP Service Pack 2)
8/16 Release to Software Update Services

[ thanks to jonathan ]