Thanks to Riccardo for posting this
Although the Windows Update 4 beta is still in progress, Microsoft is preparing for the beta of its next generation Windows Update, version 5. The vision for Windows Update V5 is to provide an efficient and effective means to keep all Microsoft products secure and up to date with the latest patches, starting with Windows, Office, SQL, and Exchange.
Testers of the current Windows Update 4 beta should be automatically accepted onto the Windows Update 5 beta due to start before the end of the year. Those who test Windows Update 5 will also be testing the Service Pack 2 of Windows XP. Windows XP SP2 is set to include Windows Update 5 as part of ensuring systems are kept up to date and secure. There is no specific date for Windows XP SP2 Beta but it"s expected to debut sometime in december.