Language Aid allows you to simply hover your mouse cursor over almost any piece of text and retrieve the information you want about it with the click of a mouse button or the tap of a keystroke. Language Aid aims to eliminate the long process of copying text, opening a web browser (or other program), loading up a web service, pasting the text and clicking a button.
One World Dictionary by Ascendo is a leading multilingual reference tool for Apple desktops.
InstantTranslate makes it really easy to translate a selection of text in the application you are working in from one language to another language.
