I've usually been copy/pasting the text from the original post for all my scans when reposting them but this one must have come from before I started the blog.
This book covers PSO Episodes I and II; it has a good ammount of developmental art for characters, settings and equipment. It also shows all of the PC costumes (this takes up a chunk of the book).
Phantasy Star Online Ep. 1 - 2 Material