Agree - I tend not to change currency at home before travelling these days. ATMs in the EC and the USA seem to accept my card, give cash at far better rates and mean that I don't have to lug large wads of cash around.
There are symbols on the back of the card which should show if the card can be read by other machines - see if it's got either the "maestro" logo or the "cirrus" logo on the back. If it has, it should work in other's countries' ATMs (provided, of course, that the back which owns the machine is also signed up to the Mastro and Cirrus conventions).