There are a few other books at Amazon:

Practical Poser 6 (Graphics Series) -- by Denise Tyler, Audre Vysniauskas; Paperback: $31.47 -- Used & new from: $31.39    - just bought, haven't opened it yet (supposed to include a stripped down Apollo Maximus on CD)
Poser 6 Revealed: The Official Guide : The Official Guide -- by Kelly L Murdock; Paperback : $15.74 -- Used & new from: $11.99    - wasn't well received because it was too basic and not much better than the manual
Secrets of Figure Creation with Poser 5 -- by B L Render; Paperback : $28.32 -- Used & new from: $28.57  - great book, but mostly geared to figure creators, so it's rather advanced.