From the very first moving-picture kiss in 1896 à la Thomas Edison, to the classic smooches we all adore in early Hollywood films, to Freud's theory of kissing as a "perverse act", this NY Times article highlights the history of kissing in film.
Above: A groundbreaking french kiss in film, actress Natalie Wood and actor Warren Beatty smooch in a parked convertible in the 1961 film "Splendor in the Grass".