I agree with XTinabell, the Holiday Tour is wonderful. It is actually the best thing we ever did at Disneyland, and that is saying a lot--considering how many times we have been there!
You can book the tour 30 days out, so mark it on your calendar 30 days prior to when you want to do it--if you are going to go on it.
It can be pricey for a larger family (I think it was 59.00 each), but totally worth it to us. The tour lasts a few hours, and you learn all there is to learn about Christmas at Disneyland--and the origins of Christmas in other countries. You get a set of headsets to listen to your tour guide, and our piped in Xmas music from his ipod to ours, and it was beyond heavenly to listen to Nat King Cole while walking through New Orleans Square! The music was half the fun. You get to walk on the rides "It's A Small World" and "Haunted Mansion Holiday" (so no line waiting), and ride the railroad. But best of all you have a perfect seat (with chair no less!) for the parade, and are given hot cocao and a christmas cookies to eat while you watch the parade.
It was so good I almost want to do it again this year! We may take another tour, though.
The parade and fireworks are different, of course. The stores are filled with Christmas items, and it is great to see all the decorations. I really love Christmas!