If you like to use the Twick.it API you should take a look at this wrappers. By simply calling some static methods you can read data from the API and don't have to care about all the REST stuff like sending HTTPrequest or parsing XML data.
Web service acts as an authorizer for other web services. It takes other service's name, client's IP address, number of requests and a key as input via GET HTTPrequest. It produces XML output saying is client authorized to use requested service.