For all the Google fans, here is the first local Google search: http://www.desktop.google.com/
I have installed it and it is a really good implementation to google.com. If you search on google.com you get in the first line the results of your local computer. The desktop search is crawling Outlook, Outlook Express, Word and Power Point and PDFs. A other feature is that the search will also search your last accessed internet websites.
(Ok, Jason Tucker was faster... )