“Simple, small, and free, Google Desktop indexes your hard drive the way Google’s own servers index the Web. Your search results are returned in a Web-page format that looks very similar to the Google Web site. The application’s sidebar regularly updates the status of your e-mail, photos, RSS feeds, and weather.
Although the initial indexing period can crawl–especially if you have a lot of e-mail, contacts, chat transcripts, and documents for it to parse through–it’s well worth the wait to be able to search any of them from a text entry box that’s installed next to the Quick Launch bar. You’ll still find the same basic gadget content: a music player, sports and stock tickers, a file shredder, and wackier items like an interactive plant. We like the Desktop sidebar’s built-in to-do list, notepad, and the capability to integrate other gadgets with ease.”
You can get it at http://download.cnet.com/Google-Desktop/3000-2379_4-10328117.html