To make a hair texture is not complex.
This is a little tutorial to teach you how to make layered hair. 

1°) Make a new image in the program Gimp. 512 / 512 pixels

2°) Fill your image with dark color.

3°) Take a soft brush and make any line in a lighter color and dark color.

4°) Chose filters and noise and scatter RGB.
uncheck correlated noise and independent RGB.

The slide bar should be 0.50.

5°) Chose filters and blur and motion blur. length= 30, angle = 90

6°) Chose filters and  blur and gaussian blur= 1, Blur Method = IIR

Your texture is finished, you can save it in TGA then load it in Second Life