In Phineas and Ferb: Across the 2nd Dimension for the PS3 and Wii, you can unlock Agent P’s “Perry The Plattyborg” skin from the Phineas and Ferb movie.
Under the Extras menu, choose Enter Code and enter the following code to unlock the extra skin:
PS3 – Circle, X, Circle, Triangle, Square, Triangle
Wii – B A B 1 2 1