Azavea has been using the OpenLayers open source Javascript mapping library for many years. OpenLayers has nice support for GoogleMaps, Bing, Yahoo, OpenStreetMap and WMS-compliant map servers. As an ESRI Business Partner, we also saw a great deal of potential for adding support for the ArcIMS and ArcGIS Server products via the respective AXL and REST API’s. Azavea staff developed extensions to OpenLayers, wrote documentation, and created samples for how to use the extensions.