Ok I decided to make a tut of how I do my coloring even though I'm not very good at icons in the first place.
For PSPX
Going from this
to this
Ok copy the image into your program. Then sharpen it once or twice, whichever works. Then hit the food fill tool set it to whatever match mode you want, doesn't make a difference. Set Blend mode to Exclusion, Opacity 25% and use a dark blue color like #0a1972. Then click your image, should look like
this. Hit it as many times as you want until you're satisfied.