If you need a wee bit help getting into the Christmas mood, here's a couple of songs and the lyrics. There's "Jingle Bells" and "Silent Night" for you to enjoy. There are lyrics for both songs in roumaji as well as the English translation so that you can sing along! :)
If that's not enough, go to http://sailormusic.net/song-collections/christmas-for-you/ for mp3s of classic Western songs and http://muza-chan.net/japan/index.php/blog/japanese-christmas-songs for original Japanese Christmas songs.