OpenDict is a free multiplatform computer dictionary. It supports popular computer dictionary formats including Slowo and Mova. It also acts as a client for DICT servers. OpenDict has plugin subsystem which lets create usable dictionaries from almost any data source.
InstantTranslate makes it really easy to translate a selection of text in the application you are working in from one language to another language.
One World Dictionary by Ascendo is a leading multilingual reference tool for Apple desktops.
