The new laws of the game are up on fifa.com.
http://www.fifa.com/mm/document/footballdevelopment/refereeing/81/42/36/log2013en_neutral.pdf
Most of the additions relate to the additional assistants, and allowing for goal line technology (referees have to test the system to fifa standards before each match, match balls have to be fifa approved or fifa inspected).
There is further clarification in the offside law
http://www.fifa.com/mm/document/footballdevelopment/refereeing/81/42/36/log2013en_neutral.pdf
Most of the additions relate to the additional assistants, and allowing for goal line technology (referees have to test the system to fifa standards before each match, match balls have to be fifa approved or fifa inspected).
There is further clarification in the offside law
• “interfering with an opponent” means preventing an opponent from
playing or being able to play the ball by clearly obstructing the opponent’s
line of vision or challenging an opponent for the ball
• “gaining an advantage by being in that position” means playing a ball
deliberately plays the ball (except from a deliberate save), is not considered
to have gained an advantage
playing or being able to play the ball by clearly obstructing the opponent’s
line of vision or challenging an opponent for the ball
• “gaining an advantage by being in that position” means playing a ball
i. that rebounds or is deflected to him off the goalpost, crossbar or an
opponent having been in an offside position
ii. that rebounds, is deflected or is played to him from a deliberate save
by an opponent having been in an offside position
A player in an offside position receiving the ball from an opponent, whoopponent having been in an offside position
ii. that rebounds, is deflected or is played to him from a deliberate save
by an opponent having been in an offside position
deliberately plays the ball (except from a deliberate save), is not considered
to have gained an advantage