This greatest of all Christmas films is on an extended run at the Prince Charles. Details here.
Chicago Reader review:
'The film Frank Capra was born to make. This 1946 release marked his return to features after four years of turning out propaganda films for the government, and Capra poured his heart and soul into it. James Stewart stars as a small-town nobody, on the brink of suicide, who believes his life is worthless. Guardian angel Henry Travers shows him how wrong he is by letting Stewart see what would have happened had he never been born. Wonderfully drawn and acted by a superb cast (Donna Reed, Beulah Bondi, Thomas Mitchell, Lionel Barrymore, Gloria Grahame) and told with a sense of image and metaphor (the use of water is especially elegant) that appears in no other Capra film. The epiphany of movie sentiment and a transcendent experience.'
Here (and above) is the trailer.