1) Download the awesome Fiddler app from here: Fiddler @ Telerik
2) Install Fiddler, then right-click its shortcut icon and click Run as Administrator.
3) Add the following configuration section within the system.net node of your web.config:
<proxy bypassonlocal="false" usesystemdefault="false" proxyaddress="http://127.0.0.1:8888" />
This section tells your server-side code to use Fiddler (running on its default port of 8888 on localhost) as its proxy for the server-side HTTP requests it makes.
Make your web service or REST calls and enjoy!