According to Google LatLong Blog(official Google blog) and Google Earth Blog(non-official), Google releases a new Google Earth plug-in (download here) for browser (currently only work on Windows). You can download it here or it will prompt you to download it the first time you go to a "Google Earth enabled" site.
Once you install the plug-in, you could experience most of the things that appear in Google Earth. Moreover, Google releases new Google Earth API (Application Program Interface) such that developer can now modify how you interact with the site. Google provides some demos to show off what developer can do with the API....
You could use the tradition Google Earth interface: code.google.com
Or being a MONSTER MILKTRUCK driver:
By the way, I just delivered milk to the tip of the world. (According to wikipedia - Coordinates 27°59′17″N 86°55′31″E / 27.98806, 86.92528)