I also found that Noise is good for making hair. There was a much more complex tutorial out there, but since Sims has so much smoothing, I played around until I found something easier. I just make a new file, fill it with noise, use wind to make it a bunch of straight lines, then adjust the hue and saturation to the color I want, play around with brightness/contrast, then use Liquify (playing with the sliders, depending on how much and where I want the waves) to get the ends to the right spots. I'm sure there's an easier way out there, but it's kinda fun to just play with it.