Earthware posted a development roadmap for Virtual Earth that was recently shared with partners in the UK --

Version 5 of the Virtual Earth map control - Early April 07
Support For Mac’s Safari Browser – Summer 07
Mobile API / Tileserver – Summer 07
Rooftop accuracy geocoding – 07 US
Polygon Searching and native GIS support
Better Custom Image Overlays
Map Metadata
Street side views
Improved 3d Model Textures
Support for a 3d Model Community
Licensing for use of imagery outside of Virtual Earth

Read more at -- Microsoft Virtual Earth Partners Day at Earthware Blog