Advertisers will be given the option of running video links under the traditional text advertising that runs alongside search results. The new links would be a box with a plus sign next to the words "watch video." When the box is clicked, a window would drop down with the video playing inside.
A Google spokesman said the new offering is a test and would only be used with a "small percentage" of searches. "The vast majority of users probably won't see this," he said.
Here are a couple of articles with more details:For now, advertisers will not pay extra to put video in the ads. They enter a price they will pay for a click in Google’s regular text-ad auction. But in the video ads, the advertiser pays when users click to see the video, even if they never click through to the advertiser’s site.
Google Tests Video Ads on Search Results Pages - Bits - Technology - New York Times Blog
Google To Test Video Ads With Search Results -- Google -- InformationWeek