21.00 GBP is currently worth 33.77 USD at a 0% Interbank rate.

You can check rates with OANDA's Currency Converter app I found for your iPod/iPhone: http://itunes.apple.com/ca/app/currency-converter/id326884235?mt=8

You can even do forex trading with OANDA's fxTrade for iPhone:

http://itunes.apple.com/ca/app/oanda-forex-trading/id370922777?mt=8

Sent from my iPhone.