The LA Times has a story on modern day coordination of military arms. (See my piece on WWII.) Basically it's a technological solution--a kit that enables remote replication of a computer monitor (think of the Slingbox which allows similar functionality for TV). Apparently the voice communications linkage was pre-existing, what the hero of the piece did was push engineers to replicate monitors of Predator operators--essentially allow one to look over their shoulder.
I've not tried it out, but apparently Microsoft has similar capability in PC's running XP or Vista. Seems like a security risk, but the coordination is worthwhile.