Microsoft has announced that Windows XP Service Pack 3 has have been RTM.  This means that OEM providers and Enterprise customers will be getting it in the next couple of days, while it is due to be released via Windows Update & the Microsoft Download Centre on April 29th.  A PDF with an overview of the contents of the Service Pack is available.

This is a much smaller update than the previous 2 SP releases, especially SP2 which added a lot of functionality, especially security.  According to the PDF

With few exceptions, Microsoft is not adding Windows Vista features to Windows XP through SP3. As noted earlier, one exception is the
addition of NAP to Windows XP to help organizations running Windows XP to take advantage of new features in Windows Server 2008.

The new features are:

• “Black Hole” Router detection turned on by default
• Network Access Protection (NAP)
• Descriptive Security Options User Interface –
  

  The Security Options control panel in Windows XP SP3 now has more
  descriptive text to explain settings and prevent incorrect settings
  configuration.

• Enhanced security for Administrator and Service policy entries –
  

  In System Center Essentials for Windows XP SP3, Administrator and
  Service entries will be present by default on any new instance of policy.
  Additionally, the user interface for the Impersonate Client After
  Authentication user right will not be able to remove these settings.

• Microsoft Kernel Mode Cryptographic Module

Unlike previous service packs, this one won’t require immediate product key activation if you don’t install it via Windows Update.  It will use the Genuine Advantage system to prompt after 30 days.  Also, as with previous version this contains all the previously released updates, but you need to be running at least Service Pack 1 to install SP3.  It is recommended that SP2 be installed first.

According to the overview PDF, the service pack will be around 70MB in size if you download through Windows Update (depending on what updates you’ve already installed) and about 580MB as a stand-alone download from the download centre.

There’s really nothing major in this release.  To be honest I’m really not sure why this was released as a service pack, why not just update the few things it adds through Windows Update?  Especially seeing as Microsoft is having such a hard time getting everyone to upgrade to Vista, surely this will only push the idea that XP is still an active & supported operating system?  This despite the fact that Microsoft is still going to stop licensing XP for OEM installs in June 2008.