Just a few things to keep in mind, though:
If you send anything that’s food, make sure it’s something store-bought that has a list of the ingredients on it. That way the soldiers know what they’re getting (it’s a bit more reassuring, for one thing, and also it would be bad to send some nice home-baked walnut cookies to some guy who’s allergic to nuts; save your home-baked goodies for your family members and close friends who are overseas). Don’t send just junk food, either. And keep in mind that it has to be able to last up to several months in shipping, and go through a lot of shaking and jolting and abuse.
If you send any clothing, try to make sure that it’s mainly natural materials (cotton, wool, linen, etc.) rather than synthetics, as many synthetics tend to react rather unpleasantly to flames and chemicals. Also, remember that bright-coloured highly-visible clothing isn’t exactly the best thing in the world to be wearing when you’re trying to sneak around and not be noticed. And though Iraq and Afghanistan have lots of desert and arid areas, it still does get cold there at night and in the Winter, so things like warm socks and bedding are always a good thing. Oh, and don’t forget the women soldiers when you’re thinking of what to send; they need to wear clothing as well. 
Things like Swiss Army knives and those little multitool things are usually good, as are AT&T calling cards, games (sports equipment, board games, those game console things), music (CD’s or MP3 players or audio cassettes), books, movies, compact musical instruments (bass cellos would be a bad idea), transformers to whatever electrical system the place uses (probably 220V), batteries, disposable cameras, foot-care products (lots of marching around and running around and wearing of boots for days on end without taking them off), little electrical heaters, brand-name teas and coffees, hobby items. . .there’s all sorts of stuff. The biggest problem on deployment is boredom, so things that will keep them entertained are needed.
And remember that whatever you send will probably have to be thrown into a bag with lots of other stuff and hauled around all over the place and dropped and banged about, so lightweight and compact and sturdy things are best. While something like a big fancy telescope might be a nice idea, it would present a few problems.
Also, send a nice letter along with the other stuff. Something from kids is usually appreciated, and pictures.
And as Bebelicious said, they want to make a good impression with the locals. So things for the kids there may be useful. School supplies, clothing, medical supplies, and games are good for this. So are small things like candy and toys that individual soldiers can carry around to hand out, although in that case they should be things that are easy to carry around and can be stuffed into a pocket and knocked about without breaking. Keep in mind that many of these kids won’t really know any English, so things with pictures may be of more use than things with words.
