Turn off blender materials

How can you turn of your blender materials (so your image is seen in the BGE)>?
I want to make a simpel menu, but in this tutorial they don’t say how to do it properly, or am I missing someting?
Tutorial:
http://blendenzo.com/tutMenu.html

Press Alt-Z to set the display to Textured mode. Also, make sure your image textures where loaded in the UV/Image window.