There will be two ways to get the new ships :
1. If you already own a valid license for Ship Sim 2006 addon pack, you can (it's already possible) download the ships of this addon, converted for Ship Sim 2008.
2. A new add on will be released, called "New Horizon". This one will contain : the ship's of the above addon, plus other new ships (a powerful harbourg tug with VSP propulsion, and a barge pusher, whose engine room will be modelled too), and plus a new navigation zone (Cornwall in great britain).
You can see screenshots of all this here :
http://www.shipsim.com/ShipSimForum/index.php/topic,4991.0.html (http://www.shipsim.com/ShipSimForum/index.php/topic,4991.0.html)
Regards,
Denis