Ok, so I decided to make a tutorial. It's my first one and I'm not too sure if I'll explain everything right. If you don't understand something, ask and I'll try to clarify.
I used a picture of Sarah from Chuck.
Going from
to
Made with Photoshop CS3 and uses selective coloring.
1- Crop and resize your image to 100x100px.
2- Duplicate your base and screen it. I put the screen layer to 25% (you may need more, adjust as such).
3- Layer > Adjustment layer > Hue/Saturation
Master = +25
Reds = -10
Set the layer to 26%.
4- Layer > New Fill Layer > Solid Color > #f8c2d9. Set it to Color Burn 25%.
5- Layer > New Adjustment Layer > Selective Color
REDS
Cyan: -100
Magenta: 0
Yellow: +100
Black: 0
YELLOWS
Cyan: +100
Magenta: +10
Yellow: -100
Black: 0
6- Layer > New Adjustment Layer > Selective Color
REDS
Cyan: -61
Magenta: +28
Yellow: +100
Black: -34
YELLOWS
Cyan: -24
Magenta: +31
Yellow: +61
Black: -32
CYANS
Cyan: +100
Magenta: 0
Yellow: -100
Black: 0
7- Layer > New Adjustment Layer > Selective Color
REDS
Cyan: -25
Magenta: 0
Yellow: +20
Black: +10
YELLOWS
Cyan: -25
Magenta: 0
Yellow: -20
Black: +10
CYANS
Cyan: +5
Magenta: 0
Yellow: -10
Black: +10
BLUES
Cyan: +5
Magenta: 0
Yellow: -5
Black: +10
NEUTRALS
Cyan: +20
Magenta: 0
Yellow: -20
Black: -10
8- Layer > New Fill Layer > Solid Color > #e2faf9. Set it to Color Burn 100%.
And you're done. :)
Other icons that I've used this coloring for: