Just got back from it and I simply loved it!
John Travolta did a excellent job as Edna, it was priceless when he was dancing with Christopher Walken.
The intergration march and song sent chills down my entire body, while "I can hear the bells" had me in fits of laughter.
I can agree that this is one of the best films of the summer, it made you feel good when it was over and was just plain entertaining!
On anther note, I saw the trailer for "Enchanted". Unlike Underdog it actually looks to be pretty good! (Love the shots of the dragon in it. ^_^)