Selective Color

Okay, I've been asked how to make an entire picture black and white except for specified highlight areas. So here's how to do it using Photoshop:

Start with a color photo like this:

Make a duplicate layer of the photo.

Make the duplicate layer black and white (there are a gazillion ways to do this, the easiest is to go to Image > Mode > Grayscale, and then adjust the Brightness and Contrast to your liking.)

Use your eraser to erase back in color highlights.

Flatten your image. Done!

In the image below, I used a soft-edged eraser to erase only the eyes from the B&W layer. I did some additional processing when converting to B&W for more of a grunge look.