If you have Poser9 or Pro2012 Sr2,1 or SR3 you can use Snarlygribbly's free EZskin2 and add Subsurface Scattering to the hair.

I couldn't get my hair prop to light up like that with EZskin2. It's a darker hair color. I'm not sure if that has something to do with it.

shedofjoy still hasn't posted his hair shader, so I'm on to exploring the viablilty of Zbrush's "fibermesh." It creates hair with a megaload of polygons, but it loads and renders fast enough, on my system at least. I'm using 16 threads to render so I can't say how well this would work with other systems.

Download my free stuff here: http://www.renderosity.com/homepage.php?page=2&userid=323368