Street View fans will have to wait a while before they can explore Olympus Mons.
The hunt for Marvin the Martian begins now!
Once you fire up Google Maps, click on Earth View (button in lower right). Zoom all the way out, click the Explore tab in the lower right, and select your celestial body of choice.
Naturally, the images used for Mars and the Moon aren't as high-res as though for the Earth, so Street View mode isn't available. However, you can still explore the surface and the major landmarks -- Olympus Mons, Sea of Tranquility, et al.
Be sure to count all the meteor strikes, and drop your totals in the comments.