Selective Greyscale
Made By Peter
Made In Photoshop CS3
Level Of Difficulty Medium

001 Find an image you want to use, I am using this photo of a Devil soft toy, I took myself.
002 Now use your preferred selection tool, Lasso or Rectangle Selection tool both work well, and select the area you want to be black and white.
003 Now, make a new Black and White layer. (Layer-> New Adjstment Layer -> Black & White) and adjust your settings to match your image, I used the following.
004 Now you are done! Feel free to add some effects to the black and white layer for more of an effect. You can see my final result below.