One of Microsoft's lesser-known stabs at Google has been “Virtual Earth”. Yesterday, Microsoft launched the publically available beta version of the world-touring software
, which is quite a marvel to look at. While there is a web portion of this software, in order to get the high-quality 3D views you need to download and install the beta, which requires Windows XP. Google earth is much more OS-friendly, and has had much more time to mature. But if you are interested in trying out Virtual Earth, the images are of outstanding quality and it's a free download. You'll need IE6 or IE7 to snag it. You can read Microsoft's official press release
at their site.