Free PlayStation 3 and Windows 7 themes are now available from the official Duke Nukem Forever site!
To install the theme on PlayStation 3, save the .P3T file to a USB drive in a folder named "THEME" inside a folder named "PS3" (caps necessary!) Put the USB drive into your PlayStation 3, navigate through settings to change your theme as usual, and the official Duke Nukem Forever theme will be available for you to install.