world-shaker:

Here are the first five:

200words-a-day If you find learning new vocabulary a time-consuming grind, try boosting it with the 200 Words a Day! language learning program offered in Spanish, French, German, and Welsh.

book2 Learn languages online for free with 100 audio (mp3) files!

Busuu A language learning community to practice your language skills.

Conversation Exchange Three types of language exchange: face-to-face conversation, correspondence, and text and voice chat.

Digital Dialects Free to use interactive games for learning languages and links to study resources.