In
Google Earth 4.3, you'll see a new icon in the menu bar which lets you easily try this for yourself:
You will then see a time slider that can control the simulated the time for the sun. Move the scroll button to change the current time, and press the play button on the right to see it animated. To change other options, such as the animation speed and the time zone, click on the clock icon to the left.
This feature also works with KMLs that contain
time animations. That way you can simulate not only data, but also how it looks at different times of day! You can also easily capture your favorite still images to share with others. Here's how you take a screen shot: