I can't play any videos on YouTube today, for some reason (all the screens are black and there's no "play" button).   But here are links to a couple of youtubes that have the intro as well as the main part of the song:

White Christmas (with intro) Ukulele Ukester Brown

from the film "Holiday Inn"

Bing Crosby Sings "White Christmas" - 12/21/68 Hollywood Palace including the intro verse