Any ideas how to change hair color in Photoshop?

Hi guys!

I really have trouble with this image...

This is a picture of my friend, I made during a walk in the forest...
And today we talked about how would black hair look on her...

So I tought, hey, I just take this image, and adjust her hair color to black...
Well it seems it much harder then I tought...

There is no problem making her hair to pink, green, blue, or even white, but i simply can't figure out haw to turn her hair to black...

Here is a link to the image: (2000x3000 in resolution, so feel free to try to adjust it.)
https://dl.dropbox.com …/20121023-161331-4391.jpg

Hope I ask for help in the right place

May be you can start by duplicating the layer, then inverting the new layer, then decrease saturation and lightness on the new layer, then use a mask to replace the hairs in the first layer by the hairs of the new layer.
This will give something like that. It's just to have an idea of the result as the masking task should be done more seriously.

I thouhgt I would give this a shot for you.
There is probably 1000 ways to do this in photoshop, but this would be my MO.

Create mask (this is a very sloppy mask)
Curves - Darken image
New layer via merge
Desaturate layer
Curves to ad highlight
Color hair highlighs with some layer blending

Result:

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

Simply make a selection roughly around the hair area with the quick selection tool. Then refine the edge painting around the hair line. Select a new adjustment layer and select "selective colouring" go through the drop down colour choices and sliders 1 by one and change to suit. 10 mins work tops to get this result. A little more time on adjustments would perfect it.

Thank you guys, much apreciated!

Will try these out!

@ Manny the Martian: I Downloaded the psd file, thank you for providing it.