Over at GameFAQs, someone posted scans of the Phantasy Star III Hint Book published by Sega back in the days of the Genesis release. If you're interested, get it while you can here:
http://www.megaupload.com/?d=WZ3CSYZ0
It's mostly the standard stuff you'd expect from a strategy guide: a walkthrough with screen shots, store lists, enemy pictures, maps, and so on. It has some neat pieces of Rhys and Maia art I've never seen elsewhere. I might add them to the galleries here in the future.
The enemy lists are very basic (just name, picture, and location), but one interesting thing is that the guide lists Twistbot, Rotabot, and Swivlbot, who are supposed to be missing from the game. Twistbot is given a location of Elysium, while the other two are listed as appearing in Mystoke Castle.