Firstly, lets look at the overall purpose of the offside rule. It was basically put in place to stop attackers from hanging by the goal and having their team kick long balls up to them. The offside rule promotes passing and prettier football.

The Rule Now to explain the rule, try to stay with me on this.

1. When a ball is passed from one player to another, the recipient of the ball must have at least two opponent players either level or in front of them when the ball is passed. (one of the opponent players will nearly always be the goalkeeper, but it can be any two players)
2. If a player receives the ball in a seemingly offside position but is in their own half then they will not be offside. You can only be offside if the recipient of the pass is in the oppositions half.
3. If the player seems in an offside position but the ball is passed backwards to them, they are not offside.
4. You can also not be offside if you receive the ball from a throw-in.

So there it is, point 1 is the main one you need to get your head around. The offside rule is really not that difficult as everyone thinks but if you think you might need to have a bit of a practical session to test it out then get out on the fields and have a kick around with your friends, guaranteed to cause no end of arguments!

With the world cup in full flow you are likely to see many arguments from players about who was offside and who wasnt, so dont be upset if you still dont understand the rule, many of the top players in the world dont seem to understand it either.