Hmm.. I don't know anything about the series you're using (or any other Japanese Language series, for that matter), but if you could tell me what file format the flash cards are provided in, that would be a good start. Also, I assume that the flash cards are subject to copyright by the publisher? My friend tells me that Anki's library may have something similar, but I would assume that they wouldn't have permission to reproduce something such as this. You could also ask around about this on the Anki mailing list. Is Anki stable on the N900 yet? I've been waiting for it for other reasons.