I would go as far to say that it's the best movie this year. It was everything I wanted to see in an animated movie. Though I still haven't seen Wall-E which, I have been told, is very good.
Thus far, this summer of movies has been far less disappointing than last years. All I really care about now is Hellboy 2 and Batman.
Go see Kung Fu Panda, if you haven't already, and enjoy the shit out of it.