The Church has created a playlist for all the Christmas videos you can access on YouTube. I've extracted one below that sums up the season.
There is also a topic page for Christmas.
Don't miss the 2010 First Presidency Christmas Devotional.
See this list of Christmas products available from the Church's Online Store.
Christmas music can be streamed from the Church's radio channel.
There are many recommendations in "Christmas spirit throughout the Bloggernacle" in Mormon Times
No Christmas is complete without Handel's Messiah.