InstantPhotoColor is a simple freeware tool for colorizing black-and-white photos.
It provides an easy and straightforward way for converting black and white or grayscale picture into the colored one.
The main tool is the coloring brush, which colorizes the parts of the photo beneath to the specified tint. When the brush is applied, the color of the surface changes, while the luminosity component remains the same, so the textures of the original picture are kept. That makes the coloring process much easier then in general purpose photo editors.
The program can also be applied for changing some parts of a color photo, for example skin, hair or eyes color.
Mac OS X 10.4.4 or later
(Via MacUpdate - Mac OS X.)