"When typing in Japanese, your iPhone uses names and readings from your address book as a kind of second dictionary for its text auto-complete. This was a very smart way to program the iPhone since the most common reason to use non-standard kanji/words to begin with is because they're used that way in a proper name (which, if it's someone/someplace/somewhere you know, would probably be in your address book anyway)."
"I previously wrote about an iPhone app called 辞書登録Lite (Jisho Tōroku) which allowed you to add words to the iPhone's Japanese dictionary and determine what yomigana input would trigger the kanji conversion. "
Kanji LS Touch is a program for iPhone/iPod Touch for learning Kanji. LS stands for Learning Software. It utilizes the unique touch interface to intuitively teach you how to draw the Kanji by displaying strokeorder guidelines.