The wording is from the FIH document available on their website (www.FIHockey.org).

2004 Rules Changes 

The changes which have been incorporated in the 2004 Rules of Hockey are relatively minor. 

Your attention is drawn to the main ones below.
 
The specification of how a penalty corner is completed has been simplified and standardised. 
Completion for substitution purposes is now consistent with completion at the end of 
half-time and full-time and is as follows: 
       a a goal is scored 
       b an attacker commits an offence 
       c the ball travels more than 5 metres outside the circle 
       d the ball travels outside the circle for the second time 
       e the ball is played over the back-line and another penalty corner is not awarded 
       f a defender commits an offence and another penalty corner is not awarded 
       g a penalty stroke is awarded. 
In relation to substitution, the penalty corner is also completed when a bully is awarded. 

However, in relation to completion at the end of half-time and full-time, if play is 
stopped because of an injury or for any other reason and no penalty has been awarded, 
the penalty corner must be taken again. 

Field players who leave the field for injury treatment, refreshment, to change equipment 
or for some reason other than substitution are permitted to re-enter only between 
the 23 metres areas. 

How the result of a match is decided is now specified: the team scoring the most goals 
is the winner but if no goals are scored, or if the teams score an equal number of goals,
the match is drawn. 

Procedures for starting and re-starting play have been rationalised.
The Rules specify that the procedures for taking a free hit now apply to the centre pass 
and to putting the ball back into play after it has passed completely over the side-line 
or back-line. 

The fundamental characteristics of the bully have been retained but it has been simplified 
by requiring sticks to touch only once. 

The former Rule which specified that a ball must not be raised intentionally so that it 
lands directly in the circle has been deleted. Wherever it lands, any ball must 
not be dangerous. 

The obstruction Rule has been simplified by referring in the Rule itself only to 
the fundamental principle that players must not obstruct an opponent who is attempting 
to play the ball. Explanatory notes will indicate that players obstruct if they 
back into an opponent, physically interfere with the stick or body of an opponent or 
shield the ball from a legitimate tackle with their stick or any part of their body. 

Players must not tackle unless they are in a position to play the ball without body contact.
 
The "advantage Rule" is specified more simply and clearly: a penalty is awarded only 
when a player or team has been disadvantaged by an opponent breaking the Rules. 
If awarding a penalty is not an advantage to the team which did not break the Rules, 
play must continue. 

The player taking a penalty stroke must start by standing behind and within playing 
distance of the ball and must not approach either the ball or the goalkeeper after taking 
the stroke. The former limitation of taking only one step forward has been deleted. 

The Rules now specify that the whistle must be blown to start a penalty stroke when 
both players are in position (rather than requiring the umpire to confirm that both 
are ready which can cause confusion in the absence of a common spoken language). 

How offences at a penalty stroke are dealt with have been rationalised. It is now clear 
that the penalty stroke is taken again if a goalkeeper prevents a goal being scored but 
leaves the goal-line or moves either foot before the ball has been played. For any 
other offence by the goalkeeper which prevents a goal being scored, a goal is awarded. 

To improve control of player conduct and therefore to protect the image of hockey, the 
intended duration of a temporary suspension may be extended for misconduct by a 
player while suspended. 

New umpiring signals have been introduced to indicate dangerous play (place one forearm 
diagonally across the chest) and stick obstruction (hold one arm out and downwards 
in front of the body half-way between vertical and horizontal; touch the forearm 
with the other hand). 

Mandatory Experimental Rules  

The two Mandatory Experimental Rules introduced in 2003 continue to apply in 2004. 
They are: 

    permitting a defender to use the stick to stop or deflect a shot at goal at any height. 
    not requiring the ball to be stopped before a shot at a goal at a penalty corner. 

These modifications of the Rules are classified as Mandatory Experiments so that 
they are scrutinised closely. Their impact on the game will be monitored by the Hockey 
Rules Board. In due course a decision will be made about whether or not 
to incorporate them as formal Rules.