well that the ball is still moving or the goalie is still in the air is irrelevant, once the ball transponded the goal line, it's a score.
Pretend the goal line on that picture is straight, then the ball is behind the line and below it, there is no way that that ball has not transponded the goal line, it is at least 2 feet in.
Or check it right here
http://www.flickr.com/photos/familiacalcagno/4743517733/?eOrig=4743499475
to me that ball is no other place that inside the goal line, even if it was for a second or two. What do you think?