Anyone know of a real-time currency rate webservice with frequent update (multiple pr. min.). Needed for a small android app I'm building, so needs to be free.
You can try Yahoo. It is free and easy to use.
For example, to convert from GBP to EUR: http://download.finance.yahoo.com/d/quotes.csv?s=GBPEUR=X&f=sl1d1t1ba&e=.csv
gives you data in csv format which can easily be parsed.