Shameless ripping of info from http://stackoverflow.com/questions/3313616/iis-express-enable-external-request

Add <binding protocol=”http” bindingInformation=”*:52591:*” />

to the <bindings> section of

%userprofile%\My Documents\IISExpress\config\applicationhost.config

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <system.applicationHost>
    <sites>
      <site name="iCentral" id="1580449741">
        <bindings>
          <binding protocol="http" bindingInformation="*:52591:*" />
        </bindings>
      </site>
    </sites>
  </system.applicationHost>
</configuration>

Note:
The snippet above is not a nearly a complete applicationhost.config, it just shows where the binding line is supposed to be in the hierarchy!