Configure proxy server for SharePoint

When adding some RSS feed web parts I realised that I need to configure a proxy server for SharePoint to access the Internet as they don’t have direct Internet access.  This is the error I was receiving:

Configuring the proxy server requires a single line in the web.config file on each front end server.  It is located in c:\inetpub\wwwroot\wss\VirtualDirectories\80 and the setting looks like this:

Once the file has been changed and saved it should take immediate effect.

I’m not aware of any way to pass credentials in the config file so any proxy that requires authentication will not work.