[Malinko]

Two ways I know how to do it. Both do the same color overlay, but at different spots.

1) Press Control+U and make sure it's on colorize. Pick the color you want. (Make sure you duplicate the layer you want colored so the strong color stays in place).

2) Go to Blending Options, click "Color Overlay" and put the option on "Hue" and select your color.

If you need more explaning, tell me =P.