to clear up the confusion: ginger beer is not alcoholic. well, sometimes it is, but it's a different beverage altogether (and apparently horrible).
ginger beer is almost the same thing, but with a little more gingery bite to it. Jamaican style ginger beer (like Goya brand, for example) is incredibly spicy. it's still good, but in a different way.
anyhoo... mix some good ginger beer with Gosling's Black Seal Rum and you got yourself one of the best mixed drinks in existence: the Dark & Stormy!
yum!