Microsoft has posted an overview of what to expect in Windows XP, Service Pack 3 (SP3). The last scheduled update of the Windows XP system includes only a small number of new functionalities. The update can be applied directly to SP2 or SP1 systems.

"Windows XP Service Pack 3 (SP3) includes all previously released updates for the operating system. This update also includes a small number of new functionalities, which do not significantly change customers’ experience with the operating system," according to Microsoft.

The update can be applied to: Windows XP, Windows XP Home Edition, Windows XP Home Edition N, Windows XP Media Center Edition, Windows XP Professional Edition, Windows XP Professional N, Windows XP Service Pack 1, Windows XP Service Pack 2, Windows XP Starter Edition and Windows XP Tablet PC Edition.

The overview page has a link to a PDF file which explains whatis in the Service Pack, new and enhanced functionality, and how to deploy. Some beta testers have reported modest (10 percent) speed gains.

When the Service pack is released, Mac users who have been running Windows XP in virtualization will find the single service pack a handy way to bring their guest Windows OS completely up to date. Microsoft told TMO that theyive only promised SP3 for "first half" of 2008, but many industry observers believe it will be well before June 30.

The public preview of XP SP3 labelled RC2 is available for download and user feedback.

Microsoft has also released Vista SP1 for download.

[Mar 25: This article was updated with addition information from Microsoft for clarity.]