I did it back in 1978 with one of the Manchester controllers in a south side flying school. Got a tour of Man ATC afterwards.
It's probably changed a lot now, but back then it encompassed a lot of stuff more related to airway work than GA flying. But as has been said, ensure you know RT procedures - what information to pass in a given situation, what must be read back, mayday, what RT terms (like "roger") mean, etc.