Not sure about the US. AOS apparently funds conservation projects. Someone on the
Native Orchid Conference may be able to fill you in on whats being done in the US.
In Australia both the Australasian Native Orchid Society parent organisation and several of the local chapters are involved in Australian orchid conservation both at the in situ and ex situ level. In Western Australia there's also the Western Australian Native Orchid Study and Conservation Group. Australia's botanical gardens and government conservation and environmental management organisations also have several orchid specific conservation projects running.
In New Zealand, New Zealand Native Orchid Group also does conservation work.