Very Nice Flashcard App
Very nicely put together. The different exercises approach memory from different angles (sound, meaning, etc.), and you only work on 10 cards at a time. If you quit the application in the middle of an exercise, it picks up where you left off. The layout is very intuitive -- you just progress down the buttons on the left side of the window.
Vocabulary is organized into different semantic classes, such as animals, body parts, etc.
It should be noted that the application deals with simplified characters, and that the focus is on recognizing characters, not writing them from memory.
Evans Bunch about Chinese FlashCards BASIC