Windows Desktop Search 3.0, which is based on Windows Vista search & indexing technology, is now available for Windows XP users. Read details:

Windows Vista Search
A couple of months ago, Microsoft released a beta preview of Windows Desktop Search 3.0 built upon Windows Vista indexing technology. Unfortunately, the preview software was not a full blown desktop search software - it ran as a service without any UI and could only be used for searching across Outlook 2007 or OneNote 2007 documents.

The good news is that Microsoft today upgraded Windows Destkop Search 3.0 program with a sleek UI and a Windows Deskbar. This new version of Microsoft desktop search software can index all kind of content (filetypes) on your Windows XP machine without requiring either Windows Vista or Office 2007.

When compared with WDS 2.6.5, you won't notice any difference in the UI but the search speed is definitely faster in version 3.0. There are still no options to select folders for indexing from the search program - you have to set a folder for indexing manually before it is included for indexing in WDS.

WindowsSeach.exe version: 6.0.5486.108

Download WDS 3.0 [WGA validation not required] | WDS 3.0 Preview | KB917013

Update: Windows Desktop Search Official blog, Find My Stuff says says they have improved the memory consumption, performance, and overall fit-and-finish.

The indexer now runs as a system service, and many other applications use the same index. This means you don’t even have to be logged in to have WDS index your hard drive – it all happens in the background. If multiple people use the same computer, there’s only one index and with no duplication of data.

The new indexing service uses the USN Journal of an NTFS volume to determine what files need re-indexing. Windows Vista allows searching the index of remote hosts, which will eventually handle many cases where you'd normally index a UNC path on many machines.