The Econtalk Podcast show (the same one that did an episode on bitcoin) touched on this a while back.
Russ compared a very talented person in Nepal to a lazy untalented teenage babysitter. The teenager made spectacularly more than a high skill individual. His theory was that the number of people the Nepalese could trade with was much smaller than Americans. Because of this, there is limited opportunity for specialization of trade in Nepal. The wages cannot be bid up, since there is not enough trade to specialize. Wages are dependent on productivity, and not specializing will make you relatively unproductive.
Bitcoin making trade easier, will help to bring wages closer together by allowing specilization. There are still a lot of other barriers to trade, but money transfer is one that bitcoin would help with.
I highly recommend this episode:
http://www.econtalk.org/archives/2010/02/roberts_on_smit.htmlFor reference, the bitcoin episode:
http://www.econtalk.org/archives/2011/04/andresen_on_bit.html