Coolest Thing Since Google Went Public

Google's Desktop Search Beta. Once it indexes your hard drive, you can search for anything on your computer using Google's UI. It even indexes your messages in Outlook so that you can find that message your boss sent three weeks ago. Having tooled around with it for an hour or so, I must say that it's one of the best, most useful pieces of software I've installed on my computer behind Star Wars Galaxies and Firefox.