Tennessee Bob: 10,000 French-related links. Find new websites, including many that allow you to practice your French vocabulary and grammar.
Bilingual Dictionaries
Wordreference.com: Bilingual dictionary
Linguee.com: French/English dictionary with short translations in context. This is an especially useful tool for idioms and other phrases that that don't translate easily.
Laboratoire d'Analyse et de Technologie du Langage: Look up a word in French and find the translation of that word and English words that are derived from it.
The ARTFL Project: French/English dictionary
French Dictionaries
Dictionnaire Electronique des Synonymes: 55,000 French words and their 410,000 synonyms
Encyclopaedia Universalis: French-language encyclopedia
Acquiring French Vocabulary (Tennessee Bob): Links to numerous general and subject-specific French-English and English-French dictionaries. Also includes links to vocabulary lists, quizzes, practice tips, crossword puzzles, games and more.
Grammar/Structure
The ARTFL Project: Conjugate French verbs
French Grammar Central (Tennessee Bob): List of links to thousands of websites that provide grammar lessons and activities.
La Conjugaison: Choose from multiple skill levels and practice your French conjugations.