I never found a thorough complete walkthrough either, which surprised me because it's a fairly popular game.
Anyway, here are some useful sites:
http://www.tgeweb.com/ironworks/wiza...ownloads.shtml contains a walkthrough for the first third of the game. Sure wish he'd finished his walkthrough, because it was just the style I like.
http://www.tk421.net/wizardry/wizardry.shtml contains a brief but complete walkthrough. Also contains some useful other information.