Frank Abagnale is a brilliant storyteller. But his story is more interesting than most. As a runaway teenager turned confidence trickster he swindled millions of dollars from banks and travelled free on airlines all round the world before serving time in prisons in France, Sweden and the US. His tale was immortalised in Steven Spielberg's film, Catch me if you Can. But for 38 years, he has been on the straight and narrow - offering his services free to the FBI and helping to combat fraud. Emma Jacobs spoke to him about how he turned his life around.