Since the release of the original phat DS. there have been talks of the super huge fighting game, Super Smash Bros. turning up on the handheld but those may have to be put on hold as Masahiro Sakurai, Creator of the series, had this to say at the GDC about it, "Seeing the success that Brawl has had with the Wii remote being playing
sideways, I don't think that there are control limitations that keep it from
being ported to the DS. But I personally have no plans to do this myself. If, in the future, such a thing was to be planned, it would be up to Nintendo to
decide how and when and in what way they would like to create that sort of game."
Touche Masahiro-San, it looks like those dreams have been squashed for now anyways.