Yves Smith of Naked Capitalism has a thoughtful review (must read) on how currency tensions are symptomatic of poorly designed and almost totally unmanaged global markets.
He forecasts that in November 3 the US Federal Reserve will take some sort of action, most likely printing dollars like crazy in search of a devaluation. However as the yuan is pegged to the dollar (at relatively low exchange rate) this should not affect so much China as the other countries and regional blocks who allow their currencies to float.
In my opinion, whatever they do other than radically reforming the global markets into something more balanced towards domestic markets (i.e. protectionism, greater governments' say in the economy) just will be another case of too little, too late. As the measures I propose are in collision course with the fundamental pillars of late Capitalism (Reaganomics, neoliberalism, Toyotism...) I am almost sure that they will not be adopted by central countries (USA, EU, Japan) unless radical political changes happen first. Instead developing countries, specially those with greater success, use them at will (no grudges here: that is what they must do if they want to avoid being swallowed by multinational corporations).