This religious organization (interfaith and non-denominational) runs Books for Soldiers which is an amazing service for our Armed Services. http://booksforsoldiers.com/
I first heard of this group through the Parade Magazine insert in my Sunday paper (Providence Journal). They were listed as a good charity to donate to soldiers through. They are registered as a 501 (c)(3).
Once you register as a donor, you are able to access the requests submitted by service men and women. Each branch is a separate page, so if you want to target the Army or the Marines, you can do so.
No administration fees are required (although they do gratefully accept small donations for the operation of the website). You are sending packages directly to the service person. Items requested range from books (of course!) to dvd's, personal care and snacks. Requests are especially heavy during the holidays, particularly Christmas/Hanukkah.
I love this program as it allows me to connect directly with the service people and send them items they really need and want.
Oh, for anyone who is concerned - religious material is not allowed to be sent (unless specifically requested). Also, no home baked items or "adult" material.
I highly recommend this program as a great way to help out our service people.