If I Didn't Know Better and Homebrew Japanese Learning
There's an e-manga available online that details the life of Samus, before she became that armour-donning lady that most of us come to know (Did I mention she transforms into a ball too?). You can view it over here but if you don't know Japanese, the nice chap at Mechadrake has a frame by frame translation over here.
Back on the Homebrew front, Drunkencoders are working on Kana DS. Quoting the site:
"Kana DS is a homebrew game targeted at new students of the Japanese language.
It aims to strengthen the player's reading and writing skills for the hiragana and katakana charsets, as well as some of the most basic kanjis. Currently, only the hiragana/katakana reference table and one of the mini-games are implemented."
And the cool thing is that this project is Open Source. Download it, tinker with it, and for more news, head over to the Drunkencoders site.