Changing color photos to black and white can take many routes. I would warn against converting to grayscale or clicking the “black and white” conversion button. If you need a quick conversion, go for it. But if you are looking to control the color details I would recommend the following link at Adobe Layers.
Using Adobe Lightroom, they suggest adjusting each level of color saturation individually and then working with the luminance to achieve your desired “look.” Be sure to make a copy and never work on the original file!
See the original color versions of these photos here.