Outlook 2007 Search Update: Windows Desktop Search 3.0 Beta 2
Windows Desktop Search 3.0 (WDS) enables fast search on your computer using indexing technology. It helps you to find your documents, email, 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 Office OneNote 2007 to index application content and deliver instant results when searching within an application.
You can get detailed information about connector on the product page http://support.microsoft.com/?kbid=917013