The ever serious minds at the Economist have released the latest in the Big Mac Index. Of note is they are starting a Tall Latte Index; Starbucks is now serving in 32 countries round the globe (the mega chain opened its first shop in France on January 16th, 2004). Both indecies use purchasing power parity (PPP) as a way of comparing bundels of goods in seperate countries. The idea being that in the long run exchange rates will move to equalize the prices, a nifty way for telling which currencies are over or undervalued.
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Jeremy Avnet knows an excellent reason for the problems caused by all those Big Macs eaten around the world.