Google has a new free desktop indexing and search program at http://desktop.google.com/ Looks just like Google. I just searched 5,472 documents in 0.02 seconds. Not as powerful as something like DTSearch, but its hard to beat the price or ease of use. Only drawback so far is that I'm not sure what file types it can index.
Its nice to see this software category go from drought to glut so quickly.