The OpenTTD Team released an update for OpenTTD 0.5 branch which fixes many known bugs and adds a few new features. You can download it with BitTorrent directly from
http://torrent.openttd.org/ (very fast).
Futher we resolved the problems we had with current 0.6 branch, so if no new problems will appear then the future of OpenTTD on MorphOS is secured for now. Thanks to all OpenTTD users who commented in the last thread here on morphzone.org (http://www.morphzone.org/modules/news/article.php?storyid=1348).
Read the full story directly on
http://www.openttd.org/ (you also find slower HTTP sourceforge.net download of the 0.5.1 release there... in case you have trouble with the BitTorrent download).