This is SUCH an important question. CNN used to be a steady, good source for just the news. Then Ted Turner sold it to Time Warner and it became just another ratings whore, just ridiculous. The sad fact is that in this country you have to pick and choose what stories to believe. If your children are in thier teens then I would suggest watching the 'Daily Show' with Jon Stewart. While thier stories have a liberal slant (liberal=intelligent) they do something more valuable- teaching that most of the news stories you hear or read have been bought and paid for.
The best source for news is The New York Times, for as long as that lasts. Try to get them to read the opinion pages, then talk about what they've read. PBS has a good source of news, but it's so boring that you want to tear your teeth out.
Bottom line: New York Times, The New Yorker magazine, Daily Show. Everyone else has an agenda, that's why they're always screaming. Because if you scream something loudly enough it starts to become truth. Make your kids one of the few who can pick and choose what to believe, because no one source out there will. Hope this helped.