Are there any programs besides Photoshop CS3 extended for doing photoshop-like effects to video?

Question

Preferably a Mac program, but Windows will work too. I need something that will help me do stuff in video like photo shop does for photos. I know CS3 extended does this, but I don't have $999 to spend.

There's a lot more to it, but the basic thing I need to do is have someone's face or body be inserted into another video scene, but have them still move. Like a green screen effect, only without the screen.

Answer 1

Once it is done Jahshaka might be the program for you:

http://en.wikipedia.org/wiki/Jahshaka