There appears to also be a PDF version, but it isn't clear whether this is exactly the same version of the document as the .PS files. It's easier to get 2-up printing from Acrobat than from raw .PS files on the Mac, though.
Also available elsewhere on Apple's site is the SDK that is mentioned in the appendix of this book.
This link is broken--I'll try to remember to fix it soon. Most of the Apple links are probably broken. :-(