Microsoft alerted me yesterday that the company has shipped the first release candidate (RC) build of Windows XP Service Pack 2 (SP2) to testers and will ship the build to the general public beginning tomorrow. XP SP2 Release Candidate 1 (RC1) contains several new features not found in earlier XP SP2 builds, including unique features for XP Media Center Edition (MCE).
  
"Microsoft has now released to testers Windows XP SP2 RC1," a company representative told me. "As you know, XP SP2 RC1 is another key milestone in the development of SP2 and is intended to provide a broad range of IT professionals and developers an opportunity to conduct testing and to prepare for deployment."
  
XP SP2 RC1's new features include the following key enhancements:
   - Security Center--a dashboard for configuring Windows Firewall, Automatic Updates, and antivirus protection, the latter of which works with third-party products
   - Microsoft Internet Explorer (IE) pop-up window blocker--turned on by default; blocks malicious Web sites from opening unwanted windows
   - New Microsoft Windows Update--a much-improved version that provides more efficient access to critical updates
   - New Windows Firewall--turned on by default; provides protection from network- and Internet-based attacks
   - Integrated Windows Media Player (WMP) 9 Series, Microsoft DirectX 9.0b, Bluetooth, Windows Update Services client, and other features released since the XP first shipped in October 2001

As previously reported, XP SP2 includes the Lonestar updates to XP Tablet PC Edition; users with Tablet PC devices will upgrade their systems to XP Tablet PC Edition 2004 when they install SP2. New to SP2 RC1 is XP MCE 2004 for Media Center PC users. XP MCE 2004 provides new features such as "improved TV picture quality, an enhanced music library, a richer photo experience, and access to music and video on demand through Online Spotlight," according to Microsoft. 
  
Microsoft made the decision to package the XP MCE 2004 and Tablet PC Edition 2004 software with SP2 to give customers the best possible security, the company representative told me. "At this time, \[PC makers\] are no longer providing Windows XP Media Center Edition 2004 upgrades," he said. "However, existing Media Center customers will be able to upgrade to Windows XP Media Center Edition 2004 via XP SP2 once it is released. By providing the Windows XP Media Center Edition 2004 upgrade as part of SP2, customers will also be able to take advantage of the security enhancements that will be in the service pack."
  
For users eager to test the new service pack, the big news is the Windows XP Service Pack 2 Technical Preview Program, through which Microsoft will distribute RC1 to interested parties. Beginning tomorrow, March 19, the program will be available from the Microsoft TechNet Web site (note that this URL won't work until sometime tomorrow).