Green Screen With The Newtek Tricaster

Check out Get Better Green Screen Results from Your TriCaster by Jeff Foster, PixelPainter.com.

"Be sure your subject is far enough from the green screen

...to avoid spill as much as possible"

Green Screen Techniques

Chromakey can be a pretty cheesy effect but there are situations where it may come in handy.  Here's a short video from TubeTape.com on greens screen techniques.