I too learn Japanese with my Nintendo DS and there is a plethora of software packages for that... Here is what I recommend:
1) 漢字そのままDS楽引辞典: This is a dictionary software for the DS, For more information, go here
2) 250万人の漢検: If your goal is to simply read kanji, this software is great, but if you want to also learn how to write kanji, this software is a must have. More info can be found here
Here is a review for 200万人の漢検 (the first game).
3) なぞっておぼえる大人の漢字練習: here is what someone wrote about it:
I am very impressed with this title. At first, it seemed a bit spartan compared to the 200万人 title below, but I prefer it A LOT over that one now. Although you may need to trial-and-error your way through menus (well, on any of these titles), this one seems to be faster-action, and better for practice as a replacement for paper-based practice. More repetitions per minute. And it has some really cool vocabulary in some mini-games (my favourite is the weather report vocab). I haven't come close to seeing the levelling of the kanji, but I think this will help anybody from starting level up to the end of the Joyou kanji.
You may want to hold a little, though, since the sequel is coming out soon
4) 正しい漢字かきとりくん: This game, originally designed for Japanese elementary school students will help you learn the first 1,006 characters (including stroke order) of Grade 1 thru 6. I believe it also has a mode that will rate your Kanji writing abilities and, of course, drills that would help you memorize them Kanji.
So even without any prior knowledge in Kanji, you will find this piece of software pretty useful, hopefully! A sequel is also coming out.
There are many, many more software packages out there. You can visit this specialized blog for more info on learning games on the NDS:
Naruhodo!
No foreign sky protected me,
No stranger's wing shielded my face.
I stand as witness to the common lot,
survivor of that time, that place.
- From 'Requiem' by Anna Akhmatova







