I came across an iPhone app that tracks all ships worldwide. It's $3.99. You can enter in your settings so you are notified via email or other method every time "your fleet" enters or leaves a port. I've tested it for the Silversea fleet and it's working pretty well. Or you can go into the app and see on a map where your fleet is. Or you can just zoom in on any area of the world and see all ships. Here's a link to the app:
http://itunes.apple.com/us/app/marinetraffic/id421227715?mt=8and here's a link to the website that it gets the info from:
http://www.marinetraffic.com/ais/
