iMovie Color Effects for Mac

From Stupendous Software:

Color Effects (32 effects, 5 free in demo version)

This package includes effects for various black and white looks, as well as color adjustment and enhancing features. Colors can be manipulated and color channels extracted and swapped. Noise and animated noise can be added to an image, and several posterized and stylized looks can be achieved. The package also includes effects for unstretching scenes shot in 16x9 widescreen format, as well as letterboxing effects for obtaining a widescreen look from standard footage.