It looks like is (finally) available for . Why bother installing this version? Well, if haven't switched to a beta of CTP build of  yet, you will probably be using any search engine to enable instant search on your computer.

After having installed on my home PC this weekend (which is still running Windows XP SP2) I'll update the Windows Desktop Search with this version later today. Even when running the Microsoft 2007 Office system applications you will be able to benefit from this version.

Windows Desktop Search 3.0 is the technology which enables instant search on your computer. It helps you to find, preview, and use your documents, e-mail, music, photos, and other items. The search engine in Windows Desktop Search 3.0 is a Windows service that is also used by applications such as Microsoft Office Outlook 2007 and OneNote 2007 to index application content and deliver instant results when searching within that application. Windows Desktop Search 3.0 provides fast indexing, improved performance, and improved file type support.
If you choose to install and use Windows Desktop Search, you can search for e-mail, documents and other files located on your computer. No information about the files on your computer will be sent to Microsoft as part of this process. Instead, Windows Desktop Search will index the content of your computer and store the index file on your computer. You can customize Windows Desktop Search to index only specified folders on your computer. Windows Desktop search will not store copies of e-mail or documents after they are deleted. After you install this item, you may have to restart your computer.

Go get it !