As Dave mentioned, the Olympics are on the networks of NBC. Here
is the site for them, and if you click on "TV Listings" you can select your local TV provider and local NBC station. I know this doesn't help on a cruise, so you'll probably have to resort to highlights on ESPN.
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas