USD/PPC corrected to PPC/USD and added some exchanges

"The quotation EUR/USD 1.2500 means that one euro is exchanged for
1.2500 US dollars. Here, EUR is the base currency and USD is the counter
currency."
http://en.wikipedia.org/wiki/Currency_pair

This ticker is from: https://btc-e.com/exchange/ppc_usd

You can see the same format here:
http://finance.yahoo.com/q?s=BTCUSD=X
http://www.google.com/finance?q=CURRENCY:BTC