Toon Shader For BGE?

I know this is for the game engine but it is also under lighting. Ok so i already searched goog and the forums but i cant seem to find a good tutorial or any information at all about how to get outlines on models in the GE(like borderlands) I belive it is called toon shading but im not sure, if someone can point me in the right direction with a script and some directions i will <3 you forever!