OK, you've installed AE6, imported a green screen shot, added it to the timeline and chosen Effect>Keying from the menu, only to find that you don't have the Keylight plug-in installed. Unfortunately, this gem of a keyer doesn't install automatically with After Effects. Not to worry, though. Just pop the AE6 installation CD back into your CD drive and find Keylight in its own folder with its own installer. Also included in this folder is a Keylight manual in Adobe Acrobat format. While there, be sure to install the Digital Anarchy 3D Assistants as well.