The movie below provides an overview of the system:
In a paper at SIGGRAPH Microsoft presented Street Slide, which combines the best aspects of the immersive nature of bubbles with the overview provided by multiperspective strip panoramas. They demonstrated a seamless transition between bubbles and multi-perspective panoramas presenting a dynamic construction of the panoramas which overcomes many of the limitations of previous systems.
As the user slides sideways, the multi-perspective panorama is constructed and rendered dynamically to simulate either a perspective or hyper-perspective view. This provides a strong sense of parallax, which adds to the immersion.
You can view the paper here (13Mb, .pdf), with Microsofts Patent recently approved, it looks like this should be coming to Bing soon.