The bottom image was created in Color Efex Pro using the Black and White effect. The key to creating this cool images was to set the filter color to yellow. Setting it to other colors produces a different effect - some good and some not so good.
When working with the Black and White filter (with Color Efex Pro and with Nik's Silver Efex pro, which is GREAT for black and white, too), play around with the color filter. You'll be quite surprised at the variations you'll get.
Explore the Light,
P.S. You can get a discount on all Nik products, as well as some other plug-ins, at the Plug-in Experience.