Adding to BAR-CODEs suggestion I would duplicate your original image to another layer and then apply your blur effect to the new layer.  Play around with Motion, Lens or Shape blur.  Once you have the angle or type of blur effect that you want you can then use a very soft brush with low opacity to erase parts of the blurred image to gradually reveal the sharp original one underneath just so that you can maintain the detail where you want it in your image.

Here is a link to one of the better methods of turning a colour image into a black and white one.

http://www.phototakers.com/articles/articles/30.html

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