"Our vision here is all about the sense of place. Photos show the local view, but videos add the sense of life. The combination of Earth's 'where' with Youtube's 'what' makes the combined experience that much more complete and compelling."
You will need to download the newest Google Earth client. Once installed, you’ll find the new layer under the "featured content" section. Each video shows up as a little YouTube logo that can be clicked for more information, including a video thumbnail preview, how many views it has, and a community rating. You can read Google’s official press release here.