Redmond (WA) - Microsoft has revamped its online Virtual Earth application to now include 3D tours of major U.S. cities. Superman wannabes can flying around the city and even down to the street level to view virtual billboards with advertiser sponsored content.

Click here to see screenshots of Virtual Earth 3D ...

Users access Virtual Earth by going to live.com, searching for something and then clicking the 'Maps' tab. So far the mapping service only works on Microsoft's Internet Explorer browser. Firefox 2 users will receive an error saying, "Firefox has detected that the server is redirecting the request for this address in a way that will never complete."

The 3D flybys are available for the following 15 cities: Atlanta, Baltimore, Boston, Dallas, Denver, Detroit, Fort Worth, Houston, Las Vegas, Los Angeles, Philadelphia, Phoenix, San Francisco, San Jose and Seattle. Microsoft promises other cities in the coming months.

Microsoft is competing against Google's Google Earth, which launched in June 2005. Google Earth requires a separate application to be installed, something that isn't required in Microsoft's Virtual Earth.