Earlier quoted context omitted.
It would be pretty nice if they partnered up with someone like Verizon and offered service in places where there is no regular 2G/3G service, your phone would need to have a chip for it I suppose.
I seem to recall that, during the initial deployment in the 90-ies, I read about China requesting that some parts of its territory be excluded from coverage. But I cannot find any links to that, and the coverage map doesn't seem to have any holes now.
I know that you have to register your phone specially to use it in russia, but I have no idea if that actually affects reachability.
I know Iridium is illegal in Kuba, but works just fine there.
I don't recall any restriction in china, currently.