Google Earth is great for viewing the Earth, but NASA World Wind is better for viewing the Moon or Mars.

Here are some World Wind views of Mars:

Like Google Earth, World Wind must be downloaded to your computer. It can be used for viewing the Earth as well, but it doesn’t have as much detailed imagery as Google Earth does. Image files are saved to your computer, so once you have viewed an area, you have quick access to the files, whether or not connected to the internet.

Google Moon has inferior imagery, and when you zoom in as far as you can go, it gets downright cheesy:

Grace and Peace