Update: Find out more about Bing Maps Streetside at Streetside View | Aerial Images | Choose Bing Maps API (microsoft.com)
In 2006, the Virtual Earth team released a new Technology Preview of street-side imagery. Take a look:
http://preview.local.live.com/
This release is not a final product, and is being released early in the development process so we can engage with the community and gather feedback on the feature concept and our implementation. We plan to integrate a more complete version of the functionality into the Windows Live Local site and the Virtual Earth platform sometime this summer. Today, only two cities are covered: Seattle, WA and San Francisco, CA, with many more to come later.
The current build is not complete and thus not ready for mashups or application development. When the feature is integrated into the platform, it will be available for developer use.
So, check it out and use the feedback button to let us know what you think!