From Tin Snips (see more from PositivelyAutism.com below!).
Jingle Bells: http://www.tinsnips.org/Media/xmas/jbells.pdf
Deck the Halls: http://www.tinsnips.org/Media/xmas/Decksong.pdf
Easy-To-Do Holiday Crafts From Everyday Household Items!: Including Crafts for Halloween, Thanksgiving, Christmas, Valentine's Day, Easter, and Every Day of the Year!
More songs from PositivelyAutism.com:
Jingle Bells: http://www.positivelyautism.com/downloads/ChristmasSongJingleBells.pdf
The First Noel: http://www.positivelyautism.com/downloads/ChristmasSongNoel.pdf