Might sound stupid but..here goes.. Help with Translating..

How do you translate Key's Air/Kanon game anyway? Do you need to have a wide knowledge about programming to do so or is there a program to use to translate these game? It would be great If there's a site I could visit that's really intended for this stuff but I don't know any site. I planned to make a translation of Air: All Age /w Voice, because my friend who doesn't understand (even just a bit) Japanese want's to play it. Anyway, I got nothing else to do anyway... so I'll devote my time to my friend.

Anyway, how did you manage to edit those PDT files? ^_^ I'd like to transate some of the picture which contains Japanese text in the PDT directory. Is there a software that converts graphics to PDT format?