dict.cc Dictionary Plug-in will be useful for all users who have to work in or with the German language. It adds a comprehensive German dictionary for offline use to your Mac Leopard glossary tool. After the installation you need to activate your new vocabulary in the preferences of Dictionary.App.
To use the dictionary you can just type a word into the built-in Dictionary application on your Mac. A list of translations will be provided, according to the different possible contexts a word might be used in. The most interesting feature though is the possibility of having this translator while you are working on almost any application or while you are surfing the net. Just right click on the unknown word in any Cocoa application and select 'Dictionary' to be able to view the translated word in English or German. Alternatively, you can hit and hold Ctrl+Command+D and move the mouse cursor over a sentence. The dictionary is also accessible via Spotlight and other core services.
It's a pity that in the descriptions provided, there is neither phonetic guidance, nor examples of how that specific item is used, but on the other hand the dictionary provides hints if you spell a word incorrectly while looking for it.
Dict.cc is a exhaustive English-German dictionary always available with a right click. Though it lacks some features, it should be a useful tool for anyone who wants to work with German on their Mac.