There has always been heated debates on whether use of the abbreviation "Xmas" takes the "Christ" out of "Christmas."
Some argue strongly against using a letter in place of sweetest Name of all.
In 2005, Franklin Graham weighed in on the matter during an interview on CNN's American Morning show:
"...for us as Christians, this is one of the most holy of the holidays, the birth of our savior Jesus Christ. And for people to take Christ out of Christmas. They're happy to say merry Xmas. Let's just take Jesus out. And really, I think, a war against the name of Jesus Christ."
Others point out that the letter "X" was frequently used for "Christ" historically.
Doug Gray has a load of information on his site of Christian symbols:
Even if there is nothing historically wrong with representing Christ with the letter "X," I tend to lean towards Graham's position.