Prozone! When I was typing the comment I was also thinking about them but couldn't remember the name. They're also a major player.
Football Manager relies on a network of 1000 scouts in 50 countries monitoring 20,000 teams. It's a useful first step in the search for the next star. Everton are the first club who signed a deal to get access to the full database.
Things have been changing really fast in the last couple of years in the football world and nowadays most clubs use all kinds of tools at their disposal. Some examples I can think of: GPS technology to track the training sessions, relying on OPTA to provide detailed statistics about matches/opponents/players and even using the database of a game such as Football Manager for their scouting network. Rafa Benitez is an example of a coach who takes it one step further but there a loads of other coaches who rely heavily upon statistics. It's an industry where there are still a lot of opportunities for entrepreneurs.