If you want to monitor the traffic to a locally hosted webservice/ website you can use Fiddler. Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. As Internet Explorer and the .NET Framework are hardcoded not to send requests for localhost through any proxies, and as a proxy, Fiddler will not receive such traffic.
A simple workaround is to use your machine name as the hostname instead of localhost. So, for instance, rather than hitting http://localhost/helloworldservice.svc , instead visit http://machinename/helloworldservice.svc.
More info on the Fidller website.