So FIFA has approved the use of goal-line technology (GLT) at the Confederations Cup in 2013 and the World Cup in Brazil 2014. The company that won the competition is GoalControl out of Germany. They use 14 cameras placed around the stadium that are fixed on the goals continually revitalizing a 3D image of the ball in comparison to the goal. It is able to give the referee a signal on his watch in less than a second if the whole of the ball has crossed the whole of the line and under the cross bar, GOAL. It has been tested extensively and was one of two systems used in the Club World Cup this past Fall 2012.
With the pressure of the games that GLT will be used I can't imagine this is a bad thing. Any help at that, or really, any level is a good thing. From an officials point of view, "Did we get it right in the end?" has always been one of the things we strive for. That said, GLT is really for the big boys only. With the preparation, people, and cost for this to work it's only feasible at the highest level. At the moment I can only imagine it being used by some of the big leagues throughout the world but not all. As it is we don't even see radio technology used extensivly yet only in the top leagues and that's a much cheaper help to the officials crew. The future will be interesting.