Google Translate - Google's free service instantly translates words, phrases, and web pages between English and over 100 other languages.
PONS - Germany’s most-trusted foreign-language dictionary. Includes language-learning materials, definitions, examples, pronunciation tips and a vocabulary trainer.
GoldenDict - The program has the following features: Use of WebKit for an accurate articles' representation, complete with all formatting, colors, images and links.
Microsoft Translator - Microsoft Translator is your door to a wider world.
Linguee - English Dictionary and Translation Search with 1,000,000,000 example sentences from human translators. Languages: English, German, French, Spanish, and Portuguese
Tatoeba - At its core, Tatoeba is a large database of example sentences translated into several languages.