PageStream, originally created for the Atari ST (remember those? I still use mine.), releases version 5.0.1.30 for x86 Linux. See newsitem http://www.osnews.com/comment.php?news_id=7789 for more + reference links.
Curious to note that some of the commentary at OSNews indicates that the previous version, 4.1, was also available for Linux. Can anyone verify this? Also, the PageStream web site ( http://www.grasshopperllc.com/ ) has apparently not been updated across all pages to reflect the new version number.
