Characters

Hey guys I was wondering if it is at all possible to input Japanese characters on an american phone; Samsung SYNC?

I don't really care if its online or anything like that, I just want to write notes and such in japanese for my class as well as maybe send texts with hiragana katakana (maybe kanji though I could live without it). Basically I'm just looking for a Japanese language firmware for the phone or just some kind of driver, I've never tinkered much with mobiles apart from installing java programs so, yeah.

tl;dr: not online, just input in hiragana+katakana (maybe kanji)