• Chinese Pronunciation Wiki Quick Start Guide, with online interactive Pinyin Chart
• AllSet Learning Pinyin ( an interactive pinyin chart for the iPad )
• Sinosplice: Review of Pronunciation Misconceptions
• ChinesePod: Pinyin Program[subscription required]
• The Rules of Pinyin

• Pleco– only partially free, but worth the money (for iPhone, Android, Windows Mobile)
• Hanping– the best free dictionary for Android devices
• MDBG– a popular free online dictionary
• nciku– perhaps the most popular free online dictionary

• The AllSet Learning Chinese Grammar Wiki
• Basic Chinese Grammar– a basic “big picture” view provided by Rutgers University
• Wikipedia: Chinese Grammar– an academic overview with linguistic value, but not well suited to actual study

• Skritter– the best online resource for practicing writing
• Chinese Character Etymology– tons of images covering the entire history of a character’s evolution
• Zhongwen.com– a hierarchical ordering of characters based on their composition

• Wenlin– a great program for Windows and Mac; paste in the Chinese text and have access to easy character readings, dictionary lookups, character info, and more
• Chinese Perapera-kun– the most popular Firefox add-on for adding popup-style readings to characters on any webpage
• Zhongwen– a simple Chrome extension for adding popup-style readings to characters on any webpage

• Chinese BBTV Radio Online[review here]
• ChinesePod

• Lang-8– write whatever you want and get free feedback from the community

Flashcards

• Anki– the most popular SRS flashcard solution [more info on SRS]

Blogs

• Sinosplice: Language(if you follow only this category, all content is related to learning Chinese)
• Hacking Chinese– In-depth discussion of issues facing learners of Chinese
• Sapore di Cina– an Italian learners’s practical suggestions for mastering Chinese
• LaowaiChinese– thoughts on learning Mandarin
• Pinyin News Blog– academic examination of pinyin in action

• “Toward Better Tones in Natural Speech”(Sinosplice)
• “Tones in Mandarin Chinese”(East Asian Student)
• ChinesePod’s Pinyin App(iOS & android, free)
• Pin Pin(iOS, free)
• Skritter(web, iOS & Android, $14.99/month)