HBO (in the US) is offering a look behind the scenes of Harry Potter and the Prisoner of Azkaban starting on May 25th at 8:45 p.m. (EST).
According to the HBO website:
A look behind the scenes of this third installment in the Harry Potter series in which an escaped convict comes after the young wizard. Daniel Radcliffe, Rupert Grint and Emma Watson star.
Please check your local listings for times and dates.