Aw, come on now - if it were a real fight, they wouldn't be able to balance up on the window sill like that :) You can also tell it's not real b/c the little one is throwing all the punches. When they're *really* fighting, she's running away and hiding under the bed.
Dang! Your cat fight has actual cat fighting!
I do like your orange cat. It'd be funny to see your orange cat fight my orange cat.