AngelList

At italki, you can get 1-on-1 language lessons from a teacher in China, Egypt, Japan, South America -- anywhere. Teachers tutor you through VOIP for as low as $4 USD / hour. italki's platform works like an ebay for language teaching services, with teachers setting their own prices and building reputations.

italki also provides a social learning experience: find language partners for practice, ask questions, and get your foreign language essays corrected by a friendly community.