Windows Defender is a free program that helps you stay productive by protecting your computer against pop-ups, slow performance and security threats caused by spyware and other potentially unwanted software.
Windows Desktop Search 3.0 is now released
Windows Media Player 11 is released
Microsoft have published a useful whitepaper on how to create an accessible web site/application.
Network Analyzer for Windows Mobile runs network utilities (e.g., ping and ipconfig) on a Windows Mobile powered device.