Company Clavis Sinica created these great apps:
CS Zika - Chinese Flashcards, CS Xiezi - Chinese Character Trainer, CS Virtues - Chinese Character Trainer, Mandy, CS Xiezi - HSK Level 1, CS Xiezi - HSK Levels 1-2, CS Xiezi - Colgate U, CS Xiezi - American U, CS Xiezi - HSK Levels 1-3, CS Xiezi - Radicals, Xiezi - Kalamazoo, Chinese Character Test, CS Xiezi - YCT, Tang Poetry for Students of Chinese, Xiezi - Holy Cross - L2, Duwen - Cornell University, Encounters Chinese Character Trainer (Simplified) - Book 1, Learn a Chinese Phrase, Marco Polo Project, Encounters Chinese Character Trainer (Traditional) - Book 1, Duwen Chinese Literacy Trainer, MSU Xiezi 101, MSU-CHS102, and others..
