Until EASA get their act together, the only qualification to hold is an FAA disptachers licence. It has been argued by many that it is not relevant to the JAA/EASA environment, but a lot of the regulations are comparable and it's still the only recognised international qualification, for example, some Airlines will not even interview you unless you hold this qualification. It isn't cheap, the courses are about 3 grand plus flights, accomodation, etc, although some Airlines will sponsor you. Also, you have to take the exam in the US which can be an issue for some people.