Google from now will showing ads on Google News search results pages in the U.S. Basically, you'll just be seeing AdWords off to the right when you enter queries, just as you would with a regular Google Search.
Not all queries will bring up ads. Searches for " Google " or " Yahoo " won't (at least for me), but a search for " Microsoft " or " Adobe " or " Kindle " will all bring up sponsored text ads.
"In recent months we've been experimenting with a variety of different formats, like overlay ads on embedded videos from partners like the AP," says Business Product Manager Josh Cohen on the Google News Blog. "We've always said that we'd unveil these changes when we could offer a good experience for our users, publishers and advertisers alike, and we'll continue to look at ways to deliver ads that are relevant for users and good for publishers, too."
Frankly, I'm surprised Google News has not been showing AdWords ads for ages now. The announcement about the ads makes no mention of similar plans for other countries.