Here is a YouTube video and more information.
The company have also launched a competition for educators.
While Google's suite of geospatial tools--Earth, Maps, SketchUp, and Sky--are used daily around the world by educators hoping to bring a fresh perspective to lessons, every once in a while a new product feature comes along that we believe will knock the socks off teachers and students alike! We're proud to announce the Ancient Rome 3D Curriculum Competition in conjunction with a brand new layer in Google Earth that models the ancient city of Rome in unbelievable detail.
For the first time ever, K-12 educators in the United States will have the chance to highlight their creativity and technical know-how by combining this brand new Google Earth content with classic classroom curricula.