Books and Cards
This is part of a japanese writing series. The first book was on Hiragana, the second book is on katakana. It is a great book with little exercises to help you master the writing! Physical flashcards are always handy whenever you are not around a computer. Take these with you while on the bus or in the car (just make sure you're not the driver.)
Websites
Wikipedia: Katakana - If you want a very thorough understanding of katakana, this is the place to go! Katakana Unicode - For the computer geeks only!
Got a link that we should post? Send Tony an email!