JCXP - The Ultimate Windows Information Site
Includes XP Tips and Tricks, Windows News, compatibility issues solved, Downloads, Forums, Longhorn Videos, and Screenshots.
Longhornfan.com
Offers software reviews, tweaks, a comprehensive and clearly arranged link list, and technical articles.
Microsoft Windows XP Training
Five-day training course for IT support professionals.
Software Tips and Tricks Forums
News and tips, drivers, desktop wallpapers, links to updates, software utilities and support forums for Windows XP.
The Elder Geek on Windows XP
Information about features and updates, including installation hints and registry tips.
TweakHound - Windows XP
Offers articles about the operating system, links, security information, troubleshooting, and updates.
Wayne's Windows XP Resources for Administrators and Users
Tips and tricks, registry and policy setting sections, utilities, tool and security focus, book recommendations and penetration testing.
Windows XP Problem and Troubleshooting Resources
A variety of hints, tips, links to Microsoft Knowledge Base Articles and other helpful pages for Windows XP.
Windows XP Resource Center
Support articles, whitepapers, links, and other resources for IT Professionals.