well, I've gotta go to school, but basically:
Cannot tackle above the shoulders.
Cannot run more than 15 metres without bouncing the ball.
The ball must travel 15 metres to be classed as a mark.
Cannot push people in the back (In a marking contest -- but you can push people in the side when going for the ball/leading etc.
Those are the basics, but I'm in a rush to get to school. Speak to you sometime. (btw, I'm going to sydney on Friday to watch the footy. ;))
~T_S