This site contains a huge number of lessons, complete with texts, vocabulary, audio, exercises and much more. And it's all free. Note that if you want to get the intermediate and advanced material,... Read more.
Olle Linge – about 8 years
Get Online Mandarin Chinese lessons from our Personal Language Tutors through Skype to increase your opportunities for career, travel and friendship or to follow your favourite Chinese film. Read more.
Sarah Thomas – over 5 years
Foreigncy has nearly 300 free Mandarin language training sets that help improve your media vocabulary, reading comprehension, and listening skills while raising your awareness of regional events. T... Read more.
Olle Linge – almost 7 years
From their website (if you have personal experience of their courses, please leave a comment):
New Concept Mandarin specializes in teaching Mandarin Chinese (Putonghua) as a second language. Act... Read more.
Olle Linge – over 7 years