ARTag SDK download
if you purchased the book you can download the Rev2K SDK for Windows, Linux, or MacOSX for free (for non-commercial private use that is) at the following link: http://www.artag.net/sdk_download/artag_sdk_download.php
there is Windows, Linux and OSX code in the SDK and there is more in the book specific download which is available from the AR book page on the pragmatic site: http://www.pragprog.com/titles/cfar (look for the "code" link)
there is Windows, Linux and OSX code in the SDK and there is more in the book specific download which is available from the AR book page on the pragmatic site: http://www.pragprog.com/titles/cfar (look for the "code" link)