ArcGIS Rest API:
9.3版本: http://resources.esri.com/help/9.3/arcgisserver/apis/rest/index.html
10版本:http://help.arcgis.com/en/arcgisserver/10.0/apis/rest/index.html
ArcGIS Rest API 相当于对ArcGIS SOAP API的加上一层封装,即Rest Services是基于SOAP Services的,一般粗略的可以理解为SOAP Services 就是Web Services。
在上层理解,ArcGIS API for Javascript/Flex/ Silverlight都是操作ArcGIS Rest API,也可以理解为对Rest API的进一步封装。