There is a new keying plug-in for Motion. And better yet, it can also work in Final Cut Pro. This plug-in will give you more keying control over your green and blue screen footage then the standard Motion keying filters. Plus you can try it out for free. The PHYX Keyer includes 5 plug-ins to help you create and refine your keys. And they are as following:

DESPILL
Instantly remove green or blue spill. Our despill algorithm effectively neutralizes spill.

DIFFKEYER
Crete mattes with any background. Green or blue screen not required.

KEYER
Three keying engines give you the power and flexibility you need to key any green or blue screen shot.

LIGHTWRAP
Realistically blend foreground and background.

SCREENCORRECTOR
Repair uneven green and blue screen footage quickly and easily.