Have you seen the ads on TV of people using Nintendo DS to learn kanji? I just saw one on TV this morning and I have been trying to find out more information about the whole thing. The software is called Kanken DS (漢検DS) because it is made by the people who produce the Kanji Proficiency Test (漢字能力検定, kanji nouryoku kentei, which is often shortened to 漢検, kanken).
It seems that the software is available through Amazon.co.jp for 3391 yen (which is less than it sells for at K’s Denki where it was about 3900 yen). The Nintendo DS machine itself costs about 22,000 yen and is also available through Amazon.co.jp (or for a bit less than that on kakaku.com).
Here is a little thingy that will let you test out the interface. Unfortunately the sample questions are quite hard, but you should be able to get a feel for the software anyway.