I highly recommend the DailyNoodles My Fun Chinese Numbers and Animals Books as a hands-on introduction to Chinese learning for kids. Included are fun crafts, coloring, matching games, Sudoku, Zodiac animals, and more!
The Greenfield 我自己会读 I Can Read series has 96 short, humorous children's stories that are illustrated beautifully and build reading confidence. The CDs give exposure to native Mandarin or Cantonese. In addition, workbooks and flashcards are included.