The built-in iPhone app called ‘Stocks’ can be used to get current and historical exchange rates for various currencies. If you only enter one code it tells you the price in that currency for one US Dollar. The format is the three-character code for that currency followed by =X. So for Euros the code is EUR=X. If you want the reverse exchange rate add that code with your source currency code. For example EURUSD=X. Remember that your bank will use buy and sell amounts that are usually 3% on either side of this rate.