I would also like to add to this list the ArcGIS API for Windows Phone. An API that allows you to add GIS capabilities to your mobile applications based on our Award winning ArcGIS API for Silverlight.  An example application that can be found in the MarketPlace that demonstrates some of the capabilities is A-to-B (http://bit.ly/a-to-b).  The API can be downloaded at: http://esriurl.com/wp7