This method is first revealed in Voiding Your Warranty: Hacking Glass session at Google I/O. If you want to go straight to see how it works, you can use this link.
In order to access to settings panel, first you need a working Android SDK, you can refer to this GDK tutorial.
Then you need to install two apps by typing following command to install them:
- adb install Settings.apk
- adb install Launcher2.apk
However Google did not release the two apks officially. But Jeff did some research on it and compiled these two apks and released them on his blog. You can either download from his site or download the following zip file.