The main hero and partner can't evolve. :(
What?! I don't have the game yet, but are you completely sure? It might be like in PMD where you have to beat the main game in order to open up a place where you have to take Pokemon to evolve...
OTHER Pokemon can evolve, just not the main 2 due to the main character, when coming from the future in the beginning of the game, made a spacial distortion.
yes you can read here
http://serebii.net/dungeon2/evolve.shtml