John Battelle, Danny Sullivan, and Andy Beal have detailed posts on the launch. All well worth reading.
Ken Fisher at Ars Technica also has some interesting tidbits:
- The Google Desktop Search works by installing a lightweight webserver on your local system, running on port 4664. Your indexed system is stored in encrypted files that you can (and should) make only accessible via SSL. The application runs on the localhost, and cannot be reached from remote systems. The end result is that searching your system feels just like using Google, and as previously mentioned, it hooks into regular Google, where you'll now see a "Desktop" tab.
Update: Jon Udell has a cute proxy hack that allows Google Desktop Search to index the Firefox browse history. But this kind of hack really shouldn't be necessary. Google needs to get to it and support more than just IE/Outlook/WinXP.