smart.fm is a great site.... There are many lists of words you can learn, including hiragana and katakana. (And, it's free... ^-^)
Also, keep in mind that you need to know not only hiragana and katakana, but also the kanji... (that will probably be easy for you, because you know Chinese already...)
If you have any questions, feel free to send me a message. ^.^
~Megumi