Windows XP Service Pack 3 (SP3) will come out yet second half of April and not as Microsoft said June. So be prepared to download or wait until June 10th for Automatic Updates!

• April 14, 2008: Support is available for the release version of Service Pack 3 for Windows XP
• April 21, 2008: Original Equipment Manufacturers, Volume License, Connect, and MSDN and TechNet subscribers
• April 29, 2008: Microsoft Update, Windows Update, Download Center
• June 10, 2008: Automatic Updates

Thanks to:Ars Technica