http://www.lego.com/eng/harrypotter/maraudersmap/mm.asp 

Good one for da kids. Hey if you get the codes let me know its driving me nuts, I mean my son is confused.

Cool, thanks I will let you know how it goes, for YOUR son lol

You have to have a Lego magazine to get the codes:(

That's what I emailed lego and they gave me a line of doodoo, that I needed to complete levels and/or pickup pieces to get the codes. Needless to say I shot one back saying they we nonresponsive.

lol well I wasn't fast enough on the pick up in the game, so I stopped trying!