http://www.dsguitar.jp/movie_list.html
One movie up, click to play.
Pretty neat app that attempts to emulate a guitar (the strumming). Supposedly you are able to pluck single notes and strum on the screen. From the looks of it, the DPAD choses chords while the stylus does the strumming.
It sounds more of an App then a game but interesting nonetheless. Should be sold via the JP amazon site. If it comes over to the US, I could see it being a direct order through amazon, similar to Electroplankton.
edit: DS plugged through an AMP.