From one warrior wife to another, I'd like to suggest you check out http://www.operationspecialdelivery.com/ for YOU. The help you get there, can help you with this, too.
I'd also like to suggest doing a belly cast when you're about 37 weeks. You can google them and see the many different ways they can turn out. You can do one and send it to your hubby, with foot prints where your baby kicks the most, you can put pictures on it, quotes, whatever...your man will love being able to put his hands "on your belly" and have that amazement. You can place baby items: a new born diaper, the "cigars" for boy/girl, a pacifier, baby socks, a onesie, etc...and place them in the belly when you ship it.
Have lots of pictures taken, even video, and then let someone put a "video" together for him to watch...you know, like all the military tributes we torture ourselves with on YouTube...like that, only it's all happy! ;o)
You may want to have a "Daddy Shower" for him over there. Send stuff for a "party" for daddy to be received two or three weeks before baby is born, too. Those guys really could use a good excuse to play--they come up with some aweful and silly things to pass the time!!! So, you could do something like that.
Work a scavenger hunt into the mix if you like...you may need a helper--one of the other guys there (or maybe a female he's serving with) with the clear understanding that if they let the cat out of the bag Iraq will seem like a trip to the day spa when they get back! lol
Good luck Sweetie, remember to do your own research and be proactive in your care. It'll all work out wonderfully.