Has anyone seen any good resources on using Bing Maps Silverlight APIs on WP7?
Another option is to use the recently released ArcGIS API for Windows Phone - currently in beta. In addition to Bing Maps support, the API has very robust capabilities for adding ArcGIS, OGC, OpenStreetMap, and client-side features (i.e. graphics) to the map.
Yes bing maps 7 silverlight for phone supports win 7 mobile. There is also support for Android and iOS.
Full details of mobile support here: http://www.georelated.com/2012/02/cloud-web-map-api-services-reviewed_19.html
Other options include google maps: Google Maps supports many mobile platforms and their html/js control is also also supported on many mobile devices. http://www.georelated.com/2012/02/cloud-web-map-api-services-reviewed.html