Getting a message to my son in Iraq-already tried the Red Cross?

My 19 yo son is in Iraq, having gone there over a month ago from his stateside post. My spouse and I had to change our number due to obscene/threatening phone calls which were occasionally being intercepted by our young children still at home. For obvious reasons, we didn't really have a choice in the matter. Since my son has been in Iraq, he has only been able to call once and we don't have a mailing address for him yet. I would at least like to get a message to him about the changed number, since we are his only point-of-contact as he is not married/having a significant other, and extended family have not bothered to be involved/interested in him in a long time to keep in touch. I know with him working 20 hour shifts in that heat as an infantryman, his morale could use a boost from occasional communications from us, be it in letter, etc (I currently have 3 care packages waiting for an address to ship them for him and the guys he's serving with). Can anyone help??