Do you learn best by scrutinizing working code created by other developers? Then you may wish to examine these two modules: RESTful Web Services creates resource representations for all entity types in order to expose them as such services. Site builders do not need to configure service endpoints because the standard Drupal paths are valid for use. The Services module differs in that it is not limited to REST, but supports JSON, JSON-RPC, XML-RPC, and SOAP, among others. It does not utilize the Entity API, and thus does not support full entity management.