They slap things up on their webiste and do a lot f editing later:
News Sniffer - About
This site, though its primary aim is to allege that the BBC censor the news, does show how much gets changed. The site does have to respond very fast to events. I saw a blog boasting that they had broken a story twenty minutes (!) before the Beeb. The downside of the speed is some sloppiness of language.
