Made in PS CS3 not translatable to PSP/GIMP (sorry)
It's quite complicated but the PSD is inside and also some options for tweaking to suit your image.
This works well with screencaps (especially stupid dark ones like SPN)
Others with tweaked settings:
Screen your base. This is always handy, right?
Then a curves layer. I changed this depending on each image (above) but this is what I put for the actual tutorial image.
in: 89, out: 107
in: 75, out: 48
in: 175, out: 215
in: 204, out 250
in: 54, out: 33
in: 94, out: 94
in: 192, out: 183
in: 70, out: 99
in: 188, out: 161
You can't be too exact with me here because I tweaked the curves when I did this on different images. You prolly need a decent knowledge of these things to pull it off.
Add a new exclusion layer of #000040
Now for channel mixer (mmm my favourite)
RED: +80, -1, +26
GREEN: +12, +105, -4
BLUE: +15, +7, +85
Colour balance layer:
MIDTONES: -4, -32, -14
SHADOWS: -22, +8, +30
HIGHLIGHTS: 0, 0, -25
Selective colour layer:
RED: -42, 0, +68, 0
YELLOW: +71, 0, -60, 0
NEUTRALS: +24, +11, +20, +7
Finally, duplicate the base on top and set to soft light.
If it's too blue mess with the curves.
Take the PSD if you want.
Comment if you do.
I'm sorry if this was overly complicated I probably made a billion mistakes, I'll come back to it when I return.
I must leave now, please give it a go and comment if you like it, I'd also like to see what you can do.