ColorWash

ColorWash helps you add drama to your photos. You can convert part of your pictures to grayscale while using the fill tool to colorize only the elements that you want to stand out.
The program can convert photos to black and white automatically, has a fast fill tool for colorizing the elements in interest and supports unlimited undo.

Moreover you can select any part of an image to restore original color.
Also you can send pictures directly to Facebook, Flickr or via email.