I know utilities to edit monster info and stuff, but not really to edit texts... (If that was text.dat, narrator or something?) I'd love to play it when it's finished though.
text.dat contains the text for all those info boxes that pop up at the bottom of the screen. And i'd be happy to point you to a copy of the mod when it's finished.
I've got the mod up and running but unfortunately I never found anything to edit text.dat, if you want to download a copy and try it i've posted a thread for it here: Hero Keeper - Dungeon Keeper Mod