How to use a green screen

You want to give the background even light about 1 stop brighter than the subject.  This will work whether the background is green, white, or whatever.

I would use 2 lights.  The light on the left should be aiming to the right corner of the background, and the light on the right to the left corner of the background.

You select and remove the image in photoshop.  Next you have to remove the fringe around the picture.  This tutorial gives some great techniques for removing the fringe.

http://tv.adobe.com/watch/the-russell-brown-show/removing-fringe/