Beagle Search is a desktop searching tool just like Google Desktop (in Windows) and Spotlight (in OS X Tiger). I have played around with it. You need to start a Beagle Deamon first for the Beagle client to work. I documented the steps where I added in a file with the searched term "DVD" and the Beagle desktop search result will automatically refresh with this new file. Not bad for an Open Source software.