As someone who lives in the boon-docks whose street (both my current and previous one) does not appear in the data for either NAVTEQ or TeleAtlas and someone who used both of those data sets extensively in his previous job, I’ve watched OpenStreetMap for awhile, although have not contributed. Marten Hogeweg, ArcGIS Server Geoportal Extension Product Manager, ESRI announce in his blogs an ArcGIS Editor for OpenStreetMap. Sounds like a great idea, giving GIS professionals–some whom have the source materials the ability to easily contribute should only help the project.