ArcBruTile display tiles from OpenStreetMap, Bing, Google, SpatialCloud and TMS/WMS-C Services in ArcGIS Desktop.

Easy ArcGIS Library is a set of C# .net classes that wrap the common functionality of ArcObjects, that help ArcGIS developers do a lot of common functions in less time and direct way.

The ArcGIS Editor for OpenStreetMap is designed to help ArcGIS users to become active members in the growing community of users building an open and freely available database of geographic data.

This project contains the source code and libraries for the Esri ArcGIS Silverlight Toolkit SDK. The library is an extension of the ArcGIS API for Microsoft Silverlight™/WPF™. Included are a number of controls, widgets and tools that you can use to enhance your web applications.

multiple map data source<--PBS-->multiple map api

GMap.NET is great and Powerful, Free, cross platform, open source .NET control. Enable use routing, geocoding and maps from Google, Yahoo!, Bing, OpenStreetMap, ArcGIS, Pergo, SigPac, Yandex, Mapy.cz in Windows Forms & Presentation, supports caching and runs on windows mobile!

MCDA4ArcMap is a multi-criteria decision analysis and interactive thematic mapping tool for ArcMap.