I saw this on national television the other night.
"Oshirikajirimushi" means "butt-biting bug."
Edit 2007-09-13: Dumb NHK had it pulled. (-_-)*
Edit 2008-02-02: I took down the ugly non-functional YouTube screen. To hear the song, you can visit the website for the upcoming Nintendo DS game.
Edit 2009-02-03: Dailymotion is hosting the video now: http://www.dailymotion.com/video/x2yxtl_fun
Hooray for subtitles!