well hopefully shippuden will come in 2009 and plus they'll probally take the money from uns and work on the other game systems projects but don't worry we'll get some naruto games and other games. and plus it takes time for the divelopers to come up with stroy modes since the original storie modes are only for the bigger systems.
It takes a long time to make a game, some of the big platform games(for 360, ect.) were started years ago, its just when it about finished when we hear about them. I would wait since anything could happen bettween now and aug 09. You never know they might be actually working on another psp naruto game, why? Well since storm is coming out for the ps3, they will proably make a psp version.