Exchange rates change every day so any answer posted here would be out of date almost immediately. While it's not normal WikiAnswers policy to say "use the Internet", that's the best approach in this...
See www.xe.com for current exchange rates.
As of January 26, 2009, the British Pound is valued at US$1.395. This means that 20 pence would be worth about 28 US cents.
It is worth US$1.45 (Jan 2012)
Since Finland uses the Euro, as of today (01APR2011), 20 Euro is worth about $28.47 US Dollars.