Zattoo delivers free Live-TV (P2P IPTV) to Linux, Windows, and Mac desktops. Depending on the country you live in you can select between multiple real TV stations to watch (if Zattoo is available in your country). This article shows how you can install the Zattoo player on an Ubuntu desktop.
I have tested this on an Ubuntu Feisty Fawn (7.04) desktop, but it should work on other versions/flavours of Ubuntu as well.
Before you can download the Zattoo player, you must register on the Zattoo web site. It's possible that Zattoo isn't available yet in your country - the Zattoo web site will tell you if this is the case.