Microsoft has released a preview of Windows Search 4.0

Windows Search 4.0 is an updated component of Windows that enables instant search on your computer.

WS4 lets you perform an instant search of your computer. WS4 helps you find and preview documents, e-mail messages, music files, photos, and other items on the computer. Please refer to the Knowledge base article KB940157 for a full description of the technology.

Note The WS4 installation process automatically upgrades previous versions of Windows Search technologies.

Windows Search 4.0 Preview for Windows XP (KB940157)
Windows Search 4.0 Preview for Windows Vista (KB940157)
Windows Search 4.0 Preview for Windows Server 2003 (KB940157)
Windows Search 4.0 Preview for Windows XP x64 Edition (KB940157)
Windows Search 4.0 Preview for Windows Vista x64 Edition (KB940157)
Windows Search 4.0 Preview for Windows Server 2003 x64 Edition (KB940157)