Free Language recently reviewed or blogged about three social language learning networks. These are not only for learning Mandarin Chinese, they are for learning any language that the collective user base can speak!

Find out more details with these articles:

MyHappyPlanet.com My Happy Planet Private Social Language-Learning Community
LiveMocha.com Live Mocha Social Language Learning Course and Networking Website
Lingopass.com Free Global Language Exchange Community

Find out about loads of resources for learning Mandarin Chinese for free at Free Language!