The ArcGIS Editor for OpenStreetMap is a free, open source add-on for ArcGIS for Desktop that helps you become an active member of the growing OpenStreetMap (OSM) community. OpenStreetMap is an open and freely available database of geographic data. The editor makes it easy for you to download OSM data, make changes to the dataset, and contribute those changes back to the entire OSM community.
The OSM Editor provides
Simple tools to upload and download OSM data
An OSM-compatible geodatabase schema to locally store OSM data
An OSM symbology template for faster editing
Conflict-resolution tools for reconciling data back to the OSM database
The ArcGIS Editor for OpenStreetMap, its documentation, and its source code are available on CodePlex, Microsoft's open source repository, and released under the Microsoft Public License.
For more information, visit ArcGIS Editor for OpenStreetMap on Github to view the source code, read the documentation, and participate in discussions, or view the flier.