Lilypond files for a bunch of Christmas Carols, which are available as a book through Amazon.com here: http://www.amazon.com/Collection-Christmas-Carols/dp/1475217552/
and from Lulu.com (in a spiral bound edition) here: http://www.lulu.com/shop/benjamin-bloomfield/a-collection-of-christmas-carols-85x11/paperback/product-20600437.html