I have a hair texture , and i took away the white background , but the white hasn't gone away yet!? I want it so all the white is gone and it only shows the colours on the texture .
There are generally four steps to make sure the viewport alpha display:
Besides, make sure Using Alpha is toggled in Texture panel, although it's set as default. And you may want to use UV as the coordinate type of texture mapping for most of the case.
However, it is interesting that you can even preview it without assigning any material, even in the default Multitexture shading mode (just like when you drag and drop an local image onto a object in the scene). And of course, it cannot be rendered, since no material assigned.