Watch live news on AppleTV
The Apple TV wasn't designed for that sort of thing; it's for all intents and purposes a closed system (i.e., iTunes-stored content only). 

At the same time, if you have a flat screen TV, then chances are you can hook up a PC or Mac to it using it as a monitor and grab newscasts off the web (a friend does this and it works great). Also some of the higher-end flat screens offer links to content distributed by the manufacturer (Sony's Bravia line comes to mind here).