APPA Currency Watcher 126.96.36.199
Not only can you get up to date currency rates, and use the currency calculator, but you can also watch currencies.
So, if you are waiting to change money, get a toast message when the rate reaches your target.
Live tiles show you up to 3 favourite rates.
Optionally get a message when the rate has changed
Requirements: Windows Phone 8.1, Windows Phone 8