Silverlight Map Viewer is a .NET native GIS viewer control
EditByBSEditor: Silverlight MAP viewer is a .NET native GIS viewer control which allows developers to Create rich interactive mapping application on web browser. It includes many useful features which you are Interest ed in, such as Overlays, Events, Popups, Minimaps, ScaleLines, Magnifier etc.
Packed with powerful AJAX interactive, simple API that makes coding easy. It is compatible with Silveright 3.0. The following topic is the feature list.

-Renderers
Draw Vectors with Shape object
Draw Vectors with WriteableBitmap object
Symbols for line, points and polygons
EPSG:900913 suppots
Auto size map

-Overlays
Request images from 3rd part WMS
Vector Overlays
Overlay to place markers or popups
OpenStreet map integrated
Bing Map supported
Google Map Supported
Yahoo Map supported (Not implement yet)

-Navigations
Continuous Panning/Zooming
Springs effect for panning, zooming or both
Integrated navigation operations
A nice looking control for panning and zooming

-Preset Tools
Navigation tools for panning and zooming
Pan-Zoom-Bar tool for zooming directly
Overview tool to see a mini map
Magnifier tool
ScaleLine tool to auto refresh when the map scale changes
Mouse coordinates to show you current world coordinates in Lon&Lat, Lat&Lon or DMS format you can free download SwiftGIS Silverlight MapViewer 1.0.206.0 now.