It’s been expected for a while, but now here it is: The YouTube layer in Google Earth, for georeferenced YouTube videos. It’s in the Featured Content folder.
Mac users need to click on the photo to go to the YouTube page to see the video. PC users get to see the video embedded in Google Earth. Currently, the time-stamp info for the video isn’t used — you can’t browse chronologically through videos for a given region, say using the time browser. Perhaps such a feature will become more pressing when there are masses more georeferenced YouTube videos out there.
Remember, you can go back to videos you have already uploaded and georeference them now. (Via PCPro)
[Update: Google's official announcement]