Examples included in the PHPoC library can be run via Arduino IDE. Here is the procedure for running the Web Client. Note that you need to connect your shield to the Internet before running this example.
Connect your shield to an AP which has the Internet connectivity according to the instructions of Connecting to an AP.
Install the PHPoC library according to the instructions of Installing The Library.
Run the Aduino IDE and select [File] > [Examples] > [PHPoC] > [WebClient].
Upload the example.
Run the serial monitor.
Check the result shown in the serial monitor.