Using your bank in this case might be the cheapest way of transfering money abroad. They will need all the details from you and charge you around 15 squid for electronic transfer.
If it is a substantial amount contact someone like moneycorp or travelex and purchase your money from the markets ..Ie you will get excellent rate of exchange (usually if you are buying a house abroad this would be the way to do it). and they will wire it over there for you for no charge usually or it will be diestable at worst.
I use western union and they are quite reasonable.
The charge is depending on how much you are sending and western union outlets can be found on most high streets.
Check out:
www.westernunion.co.uk
Hmmmm so far everyone has a different opinion of how to send money abroad whether it be Travelex, Post Office or Western union. I must say, I tried Western Union this one time and it was VERY expensive!