Bill,
It's a great idea but it doesn't work. You can check it yourself on snopes. If you want to do this then send the cards to the Red Cross, Lynda has been sending cards the last few years.
Holiday Mail For Heroes
PO Box 5456
Capitol Heights, MD
20791-5456
Here is link to snopes about it.
http://www.snopes.com/politics/chris...ldiercards.asp
Please check it out and send the those cards. Just make sure they get to the men and women that deserve them.