I also came from a video background and miss Chromakey and it's big brother Ultimatte. Have no fear, the crude methods available in Photoshop work fine, if you set the shot up correctly.
Here's my way, step by step
1. Light your backdrop (green, blue, white, whatever) as flat and even as possible (no highlights or shadows - same as you did in video). This is important as you want the background to be as close to monochrome as possible.
2. In Photoshop, use the Magic Wand Tool (selection tool) it's located second from top on right side of tool menu
3. Set the Tolerance to about 12 (controls are located just below the Filters pulldown menu) Click on your background color.
4. Open the Select pulldown menu and choose Similar. This should highlight all the background. If not, change the tolerance to a higher number and repeat.
5. With all the background highlighted, my next step is to go to the Select menu and click on Invert. The I copy the selected image and make a selerate layer using the Layer, New via Copy
6. My final step is to clean up the copied layer with the eraser or clone brush, then replace the background with another image.
Note: On more complex backgrounds, I use Corel Knockout 2 or Photoshop Extract to fine tune the process. In the image below, Jenna was not on fire. [img]/ubbthreads/images/graemlins/shocked.gif[/img]