Our website www.jinglegram.com just launched last week and it offers
personalized letters and video greetings from Santa Claus.  We created
a special FREE G.I. Jingle for men and women in the military to send a
personalized Jinglegram Greeting to their kids back at home.  Who are
the "right people" for us to contact in the U.S. military to spread
the good word of this fun, festive product so we can start having a
positive impact on morale asap?  And how can we contact these people? 
Besides direct military personnel, what other channels, websites, etc.
should we contact to spread the word of this opportunity?

I'm in the Marine Corps and I know that MCCS handles that stuff.  Here
is their website http://www.usmc-mccs.org/.  Here is the contact page
as well
http://www.usmc-mccs.org/dobusiness/sponsorpoc.htm.  Sorry I don't
know anything about the other services.
I hope this helps.

it's a great start, thank you!