If you have a Mac and it has the Leopard Operating System, then you have Photo Booth. If you do not see it in the lower icon tray, then you can find it in the applications folder from the desktop Macintosh HD icon. Once you find the Photo Booth icon, drag it to your icons tray.
What is nice about this version of Photo Booth is that it has the capability of inserting a static (still) image or a dynamic (moving) image behind you as you record yourself in front of the image. It is very easy work with and gives, you the teacher, a great way to demonstrate a lesson or students the ability to create great projects. Creating is at the top of the updated Blooms Taxonomy model, so this is just another way to create, design and develop. Look under the TUTORIALS tab for step by step instructions on how to create a presentation using Photo Booth and its green screen properties.